Methods of treating inflammation using soluble il-17ra/rc fusion proteins

ABSTRACT

Disclosed are antagonists of IL-17A and IL-17F. The antagonists are based on soluble IL-17RA and IL-17RC fusion proteins, including hybrid soluble receptors comprising portions of both IL-17RC and IL-17RA (“IL-17RC/IL-17RA”). Such antagonists serve to block, inhibit, reduce, antagonize or neutralize the activity of IL-17F, IL-17A, or both IL-17A and IL-17F. Also disclosed are methods of using such antagonists for treating disease, particularly inflammatory diseases mediated at least in part by IL-17A and/or IL-17F.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of allowed U.S. patentapplication Ser. No. 13/293,384, filed Nov. 10, 2011, which is acontinuation of U.S. application Ser. No. 12/828,041, filed Jun. 30,2010, now U.S. Pat. No. 8,084,231, which is a divisional of U.S. patentapplication Ser. No. 12/055,597, filed Mar. 26, 2008, now U.S. Pat. No.7,790,676, which claims the benefit of U.S. Provisional PatentApplication Nos. 60/983,822, filed Oct. 30, 2007, and 60/908,554, filedMar. 28, 2007, each of which is herein incorporated by reference in itsentirety.

BACKGROUND OF THE INVENTION

Cytokines are soluble, small proteins that mediate a variety ofbiological effects, including the regulation of the growth anddifferentiation of many cell types (see, for example, Arai et al., Annu.Rev. Biochem. 59:783 (1990); Mosmann, Curr. Opin. Immunol. 3:311 (1991);Paul and Seder, Cell 76:241 (1994)). Proteins that constitute thecytokine group include interleukins, interferons, colony stimulatingfactors, tumor necrosis factors, and other regulatory molecules. Forexample, human interleukin-17 is a cytokine which stimulates theexpression of interleukin-6, intracellular adhesion molecule 1,interleukin-8, granulocyte macrophage colony-stimulating factor, andprostaglandin E2 expression, and plays a role in the preferentialmaturation of CD34⁺ hematopoietic precursors into neutrophils (Yao etal., J. Immunol. 155:5483 (1995); Fossiez et al., J. Exp. Med. 183:2593(1996)).

Receptors that bind cytokines are typically composed of one or moreintegral membrane proteins that bind the cytokine with high affinity andtransduce this binding event to the cell through the cytoplasmicportions of the certain receptor subunits. Cytokine receptors have beengrouped into several classes on the basis of similarities in theirextracellular ligand binding domains.

The demonstrated in vivo activities of cytokines and their receptorsillustrate the clinical potential of, and need for, other cytokines,cytokine receptors, cytokine agonists, and cytokine antagonists. Forexample, demonstrated in vivo activities of the pro-inflammatorycytokine family illustrates the enormous clinical potential of, and needfor antagonists of pro-inflammatory molecules.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are graphic representations of the exon structure ofhuman IL-17RCx1 (SEQ ID NO:2). For those amino acid where codon wasspliced by exon/intron junction, the junction was moved to include theentire codon.

FIGS. 2A and 2B are graphic representations of the exon structure ofhuman IL-17RCx4 (SEQ ID NO:166).

FIG. 3 is a graphic representation of the exon structure of humanIL-17RA (SEQ ID NO:21).

FIGS. 4A and 4B are graphic representations of the exon structure of apreferred soluble polypeptide of the present invention as describedherein and in SEQ ID NOs:157 and 158. This soluble polypeptide comprisesexons from both human IL-17RA (SEQ ID NO:21) and human IL-17RCx1 (SEQ IDNO:2).

FIG. 5 is a graphical representation of a typical assay result using theprotocol outlined in Example 34. The graph was generated using the Prizmsoftware program. The Y values represent the MFI normalized to maximumand minimum (100% and 0%) based on ligand only and no ligand/no solublereceptor control wells, and thus the percent binding of the ligand tothe cells. The software calculates the IC50 for each curve.

FIG. 6 shows efficacy of mIL-17RA-Fc treatment in a mouse model ofGraft-versus-host disease (GVHD). Recipient mice (C57BL/6 XDBA/2 F1)were divided into treatment groups (PBS or mIL-17RA-Fc). MurineIL-17RA-Fc treatments were administered by intraperitoneal injection(150 μg per injection) every other day beginning on day—1 and continuinguntil day 15. On day 0, 80 million donor splenic lymphocytes from B6mice were injected intravenously into recipient mice (C57BL/6 XDBA/2 F1(BDF1); n=10 per group) mice. Mice were monitored 3 times a week forchanges in body weight, a hallmark sign of worsening disease in thismodel. Body weight loss in the IL-17RA-Fc treatment group (opentriangles) was not severe, and there was significantly less body weightloss (p<0.05) than in PBS controls (solid diamonds).

DETAILED DESCRIPTION OF THE INVENTION

The present invention addresses these needs by providing antagonists topro-inflammatory cytokines IL-17A and IL-17F. Specifically, thepro-inflammatory cytokines IL-17A and IL-17F have a high degree ofsequence similarity, share many biological properties, and are bothproduced by activated T cells. They have both been implicated as factorsthat contribute to the progression of various autoimmune andinflammatory diseases including rheumatoid arthritis and asthma. Infact, reagents that negate IL-17A function significantly amelioratedisease incidence and severity in several mouse models of human disease.IL-17A mediates its effects through interaction with its cognatereceptor, the IL-17 receptor (IL-17R), but the receptor for IL-17F hadnot yet been identified. Previously, we had reported that IL-17RC is areceptor for both IL-17A and IL-17F, and binds both with a similar highaffinity. IL-17R on the other hand, binds IL-17A with high affinity, butbinds IL-17F with very low affinity. Consistent with this, it has beenshown that a soluble form of IL-17R blocks IL-17A binding and signalingin cells expressing either receptor, but does not interfere with bindingor function of IL-17F to IL-17RC.

Since IL-17A intervention has been proposed as an effective therapy forseveral auto-immune diseases, using the antagonists of the presentinvention, which may block, inhibit, reduce, antagonize or neutralizethe activity of IL-17A, IL-17F, or both IL-17A and IL-17F, which includesoluble IL-17RC and IL-17RC/IL-17RA receptors, will have advantages overtherapies that target only one of these two cytokines. The inventionfurther provides uses therefor in inflammatory disease, as well asrelated compositions and methods.

A) Overview

Immune related and inflammatory diseases are the manifestation orconsequence of fairly complex, often multiple interconnected biologicalpathways which in normal physiology are critical to respond to insult orinjury, initiate repair from insult or injury, and mount innate andacquired defense against foreign organisms. Disease or pathology occurswhen these normal physiological pathways cause additional insult orinjury either as directly related to the intensity of the response, as aconsequence of abnormal regulation or excessive stimulation, as areaction to self, or as a combination of these.

Though the genesis of these diseases often involves multi-step pathwaysand often multiple different biological systems/pathways, interventionat critical points in one or more of these pathways can have anameliorative or therapeutic effect. Therapeutic intervention can occurby either antagonism of a detrimental process/pathway or stimulation ofa beneficial process/pathway.

Many immune related diseases are known and have been extensivelystudied. Such diseases include immune-mediated inflammatory diseases(such as rheumatoid arthritis, immune mediated renal disease,hepatobiliary diseases, inflammatory bowel disease (IBD), psoriasis, andasthma), non-immune-mediated inflammatory diseases, infectious diseases,immunodeficiency diseases, neoplasia, etc.

T lymphocytes (T cells) are an important component of a mammalian immuneresponse. T cells recognize antigens which are associated with aself-molecule encoded by genes within the major histocompatibilitycomplex (MHC). The antigen may be displayed together with MHC moleculeson the surface of antigen presenting cells, virus infected cells, cancercells, grafts, etc. The T cell system eliminates these altered cellswhich pose a health threat to the host mammal. T cells include helper Tcells and cytotoxic T cells. Helper T cells proliferate extensivelyfollowing recognition of an antigen-MHC complex on an antigen presentingcell. Helper T cells also secrete a variety of cytokines, i.e.,lymphokines, which play a central role in the activation of B cells,cytotoxic T cells and a variety of other cells which participate in theimmune response.

A central event in both humoral and cell mediated immune responses isthe activation and clonal expansion of helper T cells. Helper T cellactivation is initiated by the interaction of the T cell receptor(TCR)—CD3 complex with an antigen-MHC on the surface of an antigenpresenting cell. This interaction mediates a cascade of biochemicalevents that induce the resting helper T cell to enter a cell cycle (theG0 to G1 transition) and results in the expression of a high affinityreceptor for IL-2 and sometimes IL-4. The activated T cell progressesthrough the cycle proliferating and differentiating into memory cells oreffector cells.

In addition to the signals mediated through the TCR, activation of Tcells involves additional costimulation induced by cytokines released bythe antigen presenting cell or through interactions with membrane boundmolecules on the antigen presenting cell and the T cell. The cytokinesIL-1 and IL-6 have been shown to provide a costimulatory signal. Also,the interaction between the B7 molecule expressed on the surface of anantigen presenting cell and CD28 and CTLA-4 molecules expressed on the Tcell surface effect T cell activation. Activated T cells express anincreased number of cellular adhesion molecules, such as ICAM-1,integrins, VLA-4, LFA-1, CD56, etc.

T-cell proliferation in a mixed lymphocyte culture or mixed lymphocytereaction (MLR) is an established indication of the ability of a compoundto stimulate the immune system. In many immune responses, inflammatorycells infiltrate the site of injury or infection. The migrating cellsmay be neutrophilic, eosinophilic, monocytic or lymphocytic as can bedetermined by histologic examination of the affected tissues. SeeCurrent Protocols in Immunology, ed. John E. Coligan, 1994, John Wiley &Sons, Inc.

Immune related diseases could be treated by suppressing the immuneresponse. Using soluble receptors and/or neutralizing antibodies thatinhibit molecules having immune stimulatory activity would be beneficialin the treatment of immune-mediated and inflammatory diseases. Moleculeswhich inhibit the immune response can be utilized (proteins directly orvia the use of antibody agonists) to inhibit the immune response andthus ameliorate immune related disease.

Interleukin-17 (IL-17A) has been identified as a cellular ortholog of aprotein encoded by the T lymphotropic Herpes virus Saimiri (HSV) (seeRouvier et al., J. Immunol., 150(12): 5445-5456 (1993); Yao et al., J.Immunol., 122(12):5483-5486 (1995) and Yao et al., Immunity,3(6):811-821 (1995)). Subsequent characterization has shown that thisprotein is a potent cytokine that acts to induce proinflammatoryresponses in a wide variety of peripheral tissues. IL-17A is adisulfide-linked homodimeric cytokine of about 32 kDa which issynthesized and secreted only by CD4⁺ activated memory T cells (reviewedin Fossiez et al., Int. Rev. Immunol., 16:541-551 (1998)). Specifically,IL-17 is synthesized as a precursor polypeptide of 155 amino acids withan N-terminal signal sequence of 19-23 residues and is secreted as adisulfide-linked homodimeric glycoprotein. Il-17A is disclosed inWO9518826 (1995), WO9715320 (1997) and WO9704097 (1997), as well as U.S.Pat. No. 6,063,372.

Despite its restricted tissue distribution, IL-17A exhibits pleitropicbiological activities on various types of cells. IL-17A has been foundto stimulate the production of many cytokines. It induces the secretionof IL-6, IL-8, IL-12, leukemia inhibitory factor (LIF), prostaglandinE2, MCP-1 and G-CSF by adherent cells like fibroblasts, keratinocytes,epithelial and endothelial cells. IL-17A also has the ability to induceICAM-1 surface expression, proliferation of T cells, and growth anddifferentiation of CD34⁺ human progenitors into neutrophils. IL-17A hasalso been implicated in bone metabolism, and has been suggested to playan important role in pathological conditions characterized by thepresence of activated T cells and TNF-α, production such as rheumatoidarthritis and loosening of bone implants (Van Bezooijen et al., J. BoneMiner. Res. 14:1513-1521 (1999)). Activated T cells of synovial tissuederived from rheumatoid arthritis patients were found to secrete higheramounts of IL-17A than those derived from normal individuals orosteoarthritis patients (Chabaud et al., Arthritis Rheum. 42:963-970(1999)). It was suggested that this proinflammatory cytokine activelycontributes to synovial inflammation in rheumatoid arthritis. Apart fromits proinflammatory role, IL-17A seems to contribute to the pathology ofrheumatoid arthritis by yet another mechanism. For example, IL-17A hasbeen shown to induce the expression of osteoclast differentiation factor(ODF) mRNA in osteoblasts (Kotake et al., J. Clin. Invest.,103:1345-1352 (1999)). ODF stimulates differentiation of progenitorcells into osteoclasts, the cells involved in bone resorption.

Since the level of IL-17A is significantly increased in synovial fluidof rheumatoid arthritis patients, it appears that IL-17A inducedosteoclast formation plays a crucial role in bone resorption inrheumatoid arthritis. IL-17A is also believed to play a key role incertain other autoimmune disorders such as multiple sclerosis(Matusevicius et al., Mult. Scler., 5:101-104 (1999)). IL-17A hasfurther been shown, by intracellular signalling, to stimulate Ca²⁺influx and a reduction in [cAMP], in human macrophages (Jovanovic etal., J. Immunol., 160:3513 (1998)). Fibroblasts treated with IL-17Ainduce the activation of NF-κB, (Yao et al., Immunity, 3:811 (1995),Jovanovic et al., supra), while macrophages treated with it activateNF-κB and mitogen-activated protein kinases (Shalom-Barek et al., J.Biol. Chem., 273:27467 (1998)).

Additionally, IL-17A also shares sequence similarity with mammaliancytokine-like factor 7 that is involved in bone and cartilage growth.Other proteins with which IL-17A polypeptides share sequence similarityare human embryo-derived interleukin-related factor (EDIRF) andinterleukin-20.

Consistent with IL-17A's wide-range of effects, the cell surfacereceptor for IL-17A has been found to be widely expressed in manytissues and cell types (Yao et al., Cytokine, 9:794 [1997]). While theamino acid sequence of the human IL-17A receptor (IL-17R) (866 aminoacids) predicts a protein with a single transmembrane domain and a long,525 amino acid intracellular domain, the receptor sequence is unique andis not similar to that of any of the receptors from the cytokine/growthfactor receptor family. This coupled with the lack of similarity ofIL-17A itself to other known proteins indicates that IL-17A and itsreceptor may be part of a novel family of signalling proteins andreceptors. It has been demonstrated that IL-17A activity is mediatedthrough binding to its unique cell surface receptor, wherein previousstudies have shown that contacting T cells with a soluble form of theIL-17A receptor polypeptide inhibited T cell proliferation and IL-2production induced by PHA, concanavalin A and anti-TCR monoclonalantibody (Yao et al., J. Immunol., 155:5483-5486 (1995)). As such, thereis significant interest in identifying and characterizing novelpolypeptides having homology to the known cytokine receptors,specifically IL-17A receptors.

The expression pattern of IL-17F appears to be similar to that ofIL-17A, such that it includes only activated CD4+ T cells and monocytes(Starnes et al. J. Immunol. 167:4137-4140 (2001)). IL-17F has beendemonstrated to induce G-CSF, IL-6, and IL-8 in fibroblasts (Hymowitz etal, EMBO J. 20:5322-5341 (2001)) and TGF-β in endothelial cells (Starneset al. J. Immunol. 167: 4137-4140 (2001)). It has recently been reportedthat IL-23, a cytokine produced by dendritic cell, can mediate theproduction of both IL-17A and IL-17F, primarily in memory T cells(Aggarwal et al. J. Biol. Chem. 278:1910-1914 (2003)).

Moreover, over expression or upregulation of both IL-17A and IL-17F havebeen shown in arthritic and asthmatic individuals (reviewed in Moseleyet al., Cytokine Growth Factor Rev 14:155-174 (2003)). With regards toarthritis, these cytokines act in a manner characteristic to thecartilage and joint destruction that is associated with rheumatoid- andosteo-arthritis. For example, IL-17A and IL-17F have been demonstratedto enhance matrix degradation in articular cartilage explants viarelease of cartilage proteoglycan glycosaminoglycans and collagenfragments, while inhibiting the synthesis of new proteoglycans andcollagens (Cai et al., Cytokine 16:10-21 (2001); Attur et al., ArthritisRheum 44:2078-2083 (2001)).

Similar to IL-17A, overexpression of IL-17F in mice has also been shownto increase lung neutrophil recruitment and result in increasedexpression of Th1-associated cytokines in the lung, including IL-6,IFN-gamma, IP-10 and MIG (Starnes et al., J. Immunol. 167:4137-4140(2001)). IL-17F was also upregulated in T cells from allergen-challengedasthmatics (Kawaguchi et al., J. Immunol. 167:4430-4435 (2001)), andfound to induce IL-6 and IL-8 production in NHBE. In contrast to IL-17A,IL-17F appears to inhibit angiogenesis in vitro (Starnes et al., J.Immunol. 167:4137-4140 (2001)).

IL-17F mRNA was not detected by northern blot in various human tissuesbut was dramatically induced upon activation of CD4⁺ T cells andmonocytes. (Id.) In mice, Th2 cells and mast cells were found to expressIL-17F upon activation. (See Dumont, Expert Opin. Ther. Patents 13(3)(2003).) Like IL-17A, the expression of IL-17F was also found to beupregulated by IL-23 in mouse.

The Il-17 cytokine/receptor families appear to represent a uniquesignaling system within the cytokine network that will offer innovativeapproaches to the manipulation of immune and inflammatory responses.Accordingly, the present invention is based on the discovery of a newIL-17 family receptor, IL-17RC and its ability to bind both IL-17A andIL-17F.

IL-17RC was initially identified using a bioinformatics approach tosearch for proteins related to IL-17RA and identified through a cDNAencoding the IL-17 receptor-related protein IL-17RC. In spite of itsobvious similarity to the IL-17 receptor (IL-17RA), which binds to theprototypical member of the IL-17 family IL-17A, and the identificationof five other members of the IL-17 cytokine family, a specific ligandfor IL-17RC had not been previously reported. However, IL-17A and IL-17Fwere identified as the specific ligands for IL-17RC as described in U.S.patent application Ser. No. 11/150,533, filed on Jun. 10, 2005 andpublished as US Patent Publication No. 20060002925. Specifically, theseligands were identified using Baby Hamster Kidney cells (BHK) that werestably transfected with constructs encoding either human IL-17RA(hIL-17RA) or IL-17RC (hIL-17RC). Expression of receptors on the surfacewas confirmed by FACS analysis using either a monoclonal antibody tohIL-17RA or a polyclonal antiserum to hIL-17RC. To assess cytokinebinding, biotinylated forms of human IL-17A, C, D, E, and F andfluorochrome-conjugated streptavidin were used to detect cytokinebinding to transfected cells by flow cytometry. The results clearlyshowed that stably transfected BHK cells expressing hIL-17RA clearlybound human IL-17A (hIL-17A) as expected, whereas those transfected withempty expression vector failed to bind any members of the IL-17 familytested. Relatively weak binding of human IL-17F (hIL-17F) tohIL-17RA-transfected cells was also observed, but there was nosignificant binding of other members of the IL-17 family tested. OtherIL-17 family members were examined for binding of tohIL-17RC-transfected cells and it was noted that these cells showedsignificant binding to hIL-17F. In addition, significant binding ofhIL-17A to these cells was seen, but no binding of hIL-17C, D, or E.This data proved that hIL-17RC was the receptor for both hIL-17F andhIL-17A.

Additionally, the level of fluorescence over a range of cytokineconcentrations was examined to determine relative affinities of hIL-17Aand F for hIL-17RA and hIL-17RC. By comparing mean fluorescenceintensities of the individual cytokines on each transfectant, it wasnoted that hIL-17A bound much better to hIL-17RA than hIL-17F did, butthat both cytokines seemed to bind equally well to hIL-17RC-transfectedcells. Interestingly, cytokine binding to cells that expressed bothreceptors seemed to be additive, with no evidence of cooperativity.

Next, the specificity of this binding was investigated by attempting tocompete for binding with unlabeled cytokine. Transfected BHK cells wereincubated with a fixed concentration of biotinylated cytokine andincreasing concentrations of unlabeled cytokine and the amount of boundbiotinylated material was quantitated by FACS. It was shown that thebinding of both hIL-17A and F to hIL-17RC was specific since increasingconcentrations of unlabeled cytokine interfered with binding of thebiotinylated material. In fact, unlabeled hIL-17A and F effectivelycross-competed for binding of biotinylated forms of both cytokines tohIL-17RC-transfected cells, suggesting that the two cytokines werebinding hIL-17RC with similar affinities, and that they were binding tooverlapping, if not identical sites. Uunlabeled hIL-17A also effectivelycompeted for binding of both biotinylated hIL-17A and F tohIL-17RA-transfected cells, while unlabeled hIL-17F showed essentiallyno ability to compete for hIL-17A binding to hIL-17RA. This indicatedthat although hIL-17F showed specific binding to hIL-17RA, the avidityof this interaction appeared to be significantly lower than theinteraction of hIL-17A and hIL-17RA.

Saturation binding studies were done to measure the affinity of hIL-17Aand F binding to hIL-17RC and hIL-17RA. BHK cell lines stably expressinghIL-17RA or hIL-17RC were incubated with iodinated hIL-17A or F undersaturation binding conditions to determine the affinity constants ofeach cytokine for each receptor. hIL-17A bound both hIL-17RA andhIL-17RC with comparable affinities (Table 1). Specifically, BHK cellstransfected with the indicated receptor were used to establish K_(d)values for hIL-17 A and hIL-17F as described in Methods. Results shownare mean K_(d) values derived from triplicate determinations.

TABLE 1 hIL-17A hIL-17F hIL-17RC (x1)¹ 0.6 nM 1.0 nM hIL-17RA 1.9 nM 1.5μM ¹Denotes the x1 splice variant of hIL-17RC.

In addition, the affinity of hIL-17F for hIL-17RC was very similar tothe affinity of hIL-17A for this receptor (see Table 1 above). However,consistent with results obtained using biotinylated cytokines, theaffinity of hIL-17F for hIL-17RA was roughly 1000-fold lower relative toother affinities measured (Id.). This indicates that hIL-17A and F bindhIL-17RC with similar affinities, but their affinities for hIL-17RAdiffer dramatically.

The observation that hIL-17RC bound both hIL-17A and F with highaffinity suggests that cells expressing hIL-17RC should be equallycapable of responding to hIL-17A and F. On the other hand, sincehIL-17RA bound hIL-17A with high affinity, but hIL-17F about 1000-foldless well, the implication is that cells expressing hIL-17RA would,under physiologic conditions, only respond to hIL-17A. Previously, ithad been shown that hIL-17RA is expressed ubiquitously, but itsexpression has been reported to be higher in hematopoietic cells withlower expression in other tissues. Therefore, the expression of hIL-17RCwas examined to determine the extent of overlap in the expressionpatterns. Northern blot analysis showed that hIL-17RC was expressed athigh levels in glandular tissues such as adrenal gland, prostate, liver,and thyroid with no detectable expression in hematopoietic tissues.

To further investigate expression of these receptors in hematopoieticcells, the binding of biotinylated hIL-17A and F to peripheral bloodmononuclear cells (PBMC) by multiparameter FACS analysis was alsoexamined. Results indicated that hIL-17A bound to virtually all PBMCsubsets examined, whereas hIL-17F failed to show detectable binding toany of these populations. This is consistent with the capacity ofhIL-17RA to bind hIL-17A with high affinity, but not hIL-17F, and withthe failure to detect hIL-17RC mRNA in PBMC. Collectively, these dataindicate that IL-17RC is preferentially expressed in non-hematopoietictissues, while IL-17RA is preferentially expressed in hematopoieticcells.

The high affinity binding of hIL-17A and F to hIL-17RC-transfected cellssuggests that an efficacious therapeutic might be a soluble form ofhIL-17RC. Such a molecule would be an effective antagonist of these twocytokines. To test this directly, a soluble form of human hIL-17RC wasproduced as an Fc-fusion protein and tested its ability to inhibit thebinding of both hIL-17A and F. These effects were then compared withresults obtained using a soluble form of hIL-17RA. Increasingconcentrations of hIL-17RC-Ig or hIL-17RA-Ig were included in bindingreactions and FACS analysis was used to assess effects of the solublereceptors on binding of biotinylated cytokines to stably transfected BHKcells. Soluble hIL-17RC inhibited the binding of both hIL-17A and F to asimilar extent, whereas an Fc-fusion protein of another member of theIL-17R family, hIL-17RD, had no effect. On the other hand, solublehIL-17RA effectively blocked binding of hIL-17A, but had essentially noeffect on the binding of hIL-17F. Similar results were obtainedexamining binding of hIL-17A to hematopoietic cells. This binding waseffectively blocked using hIL-17RA-Ig and hIL-17RC-Ig, but nothIL-17RD-Ig. These data are consistent with results obtained fromaffinity measurements and indicate that the soluble receptors arebehaving the same as their membrane-anchored forms.

As an additional assessment of the capacity of the human hIL-17RC-Ig tobind to hIL-17A and F, the affinity of the soluble receptor for thesecytokines was assessed using Biacore analysis. Soluble hIL-17RC bound toboth hIL-17A and F with high affinity (Table 2), providing additionalsupport for the idea of using this reagent as an antagonist for theeffects of both hIL-17A and F in vivo. Specifically, soluble receptorswere captured onto chips and binding experiments were performed asdescribed below. ND=no detectable binding.

TABLE 2 k_(a) (on-rate) k_(d) (off-rate) K_(D) hIL-17RC-Ig mIL17A NDmIL17F ND hIL17A 1.05E+06 4.90E−04 0.469 nM 1.24E+06 4.38E−04 0.352 nMhIL17F 9.91E+05 4.31E−04 0.435 nM 1.11E+06 3.84E−04 0.346 nM mL-17RA-IgmIL17A 9.78E+05 6.79E−05 0.069 nM 1.12E+06 7.99E−05 0.072 nM mIL17F ND

The number of splice variants in humans is much greater and therefore weperformed our initial experiments on only a subset of these molecules.Those chosen for this analysis also differed in their inclusion orexclusion of exon 7, but, unlike the mouse, all splice variantsincorporated all of exon 8. The cryptic splice acceptor found in themiddle of the mouse exon 8 sequence is not present in human exon 8.However, the other splice variants tested either included or excludedhIL-17RC exon 12. These variants were designated hIL-17RCx1 (identicalin exon composition to mouse x1 above), hIL-17RCx4 (identical in exoncomposition to mouse x4 above), hIL-17RCx2, and hIL-17RCx7. Again, thesesplice variants were transiently expressed in 293F cells and were testedfor their ability to bind biotinylated mouse and human IL-17A and F andthe results are summarized in Table 3.

TABLE 3 Cytokine Binding² Exons¹ hIL- mIL- Variant 7 8 12 17A hIL-17FmIL-17A 17F Human IL-17RCx4 + + + + + − + IL-17RCx1 − + + + + − −IL-17RCx2 − + − − − − − IL-17RCx7 + + − − − − − ¹Denotes exonscompletely included in transcript. ²(+) indicates a detectable,significant cytokine binding as assessed by a significant increase influorescence by FACS. (−) indicates no significant change influorescence.

Consistent with the experiments presented earlier, hIL-17RCx1 bound toboth hIL-17A and F, but did not bind to either mouse cytokine.hIL-17RCx4 also bound to both human cytokines, and like its mousecounterpart, it bound to mIL-17F, but not mIL-17A. hIL-17RCx2 and x7failed to bind any of the four cytokines tested, although they wereclearly expressed on the surface of transfected cells since a polyclonalantiserum against hIL-17RC stained CD8⁺ cells (data not shown). Thesebinding results were faithfully recapitulated in stably transfected BHKcells as well. Collectively, these data support conclusions regardingessential portions of the IL-17RC protein required for binding to thehuman cytokines.

Numerous publications have implicated IL-17A and, to a lesser extent,IL-17F as contributing to disease progression and severity in mousecollagen-induced arthritis (CIA) and human rheumatoid arthritis. Theexpression of both mIL-17A and F in the joints or draining lymph nodes(DLN) from mice that had been immunized with collagen to induce CIA wasexamined. Analysis by real-time PCR clearly demonstrated that bothcytokines were upregulated in both tissues in diseased mice relative tounimmunized controls, clearly indicating that expression correlated withdisease. In addition, the relative expression of mIL-17RA and mIL-17RCwas also examined in the same tissues. However, in this case, there wasnot a reproducible correlation of expression of either receptor withdisease. Moreover, what was obvious was the discrepancy in expressioncomparing DLN to non-hematopoietic tissue (hind foot). Consistent withthe previous results looking at expression of the human receptors,mIL-17RA was found to be more highly expressed in hematopoietic tissue,and mIL-17RC to be more highly expressed in non-hematopoietic tissue.This data suggests that expression of mIL-17A and mIL-17F expressioncorrelates with disease, that both of the requisite receptors arepresent in diseased and normal tissue, and suggests that neutralizationof these cytokines may be an effective therapy to prevent diseaseprogression.

Accordingly, the cognate receptor for IL-17A and F has been shown to beIL-17RC. Notably, hIL-17RC binds to hIL-17A and F with similaraffinities. Since these two members of the IL-17 family share 55%sequence identity, it is perhaps not surprising that they sharereceptors. However, hIL-17RA binds hIL-17A with high affinity, but bindshIL-17F with an affinity that is nearly 1000-fold lower, suggesting thatunder physiologic conditions, hIL-17RA would not bind hIL-17F. Theimplication is that cells that express hIL-17RC should respond to bothhIL-17A and F, whereas cells that only express hIL-17RA will onlyrespond to IL-17A. This difference has the potential to impact how thesecytokines affect different tissues. Through expression analysis it wasshown that although IL-17RA is expressed ubiquitously, it is more highlyexpressed in hematopoietic cells, whereas IL-17RC tends to be expressedin non-hematopoietic tissues with no expression in hematopoietic cells.Consistent with this, all subsets of human peripheral blood mononuclearcells bind hIL-17A, but do not bind hIL-17F. Moreover, this suggeststhat non-hematopoietic tissues should respond to both IL-17A and F,whereas hematopoietic cells should only respond to IL-17A.

This examination of cytokine binding to the different IL-17RC splicevariants has revealed two portions of the receptor that are essentialfor cytokine binding, and there are subtle differences in the bindingcharacteristics of the mouse and human cytokines. Moreover, thesecharacteristics are consistent for the cytokines regardless of thespecies of the receptor examined. As shown from the data presented inTable 3, exon 12 and all of exon 8 are required for hIL-17A and F tobind to IL-17RC, since these cytokines only bind to the human x1variants and the human x4 variants. Each of these isoforms includes allof exon 8 and exon 12, although they differ with respect to whether exon7 is included or not. This implies that exon 7 is dispensable forbinding of the human cytokines.

The importance of generating an antagonist to both IL-17A and IL-17Ffunction seems clear from available information that shows a strongcorrelation between IL-17A and F expression and progression of a numberof autoimmune and inflammatory diseases. These two cytokines induceother inflammatory cytokines and chemokines as well as matrixmetalloproteases, which contribute to collagen and bone destruction inautoimmune arthritis. This reagent should serve as an effectivetherapeutic for rheumatoid arthritis and in other inflammatory diseasesin which hL-17A and F play a role.

Thus, soluble forms of human IL-17RC were developed to serve as anantagonist to both IL-17A and IL-17F. Therapeutically, these solubleIL-17RC polypeptides were efficacious. However, due to numerous factors,soluble IL-17RC is not easily secreted from the numerous and varyingproduction systems available in the art. Nor is it secreted in adequatequantities needed for manufacturing purposes. Thus, there is a need inthe art to develop antagonists to IL-17A and IL-17F that can beexpressed and secreted in quantities that can be scaled up formanufacturing.

Accordingly, the present invention answers this need by providing IL-17Aand IL-17F antagonists that can be expressed and secreted. Specifically,the present invention is based on the development and discovery of anumber non-naturally occurring soluble molecules or soluble polypeptidesthat bind to, antagonize and/or block the binding of IL-17A and IL-17Fto their cognate receptor(s). These soluble polypeptides compriseportions of IL-17RC. These soluble polypeptides can also compriseportions of both IL-17RC and IL-17RA (“IL-17RC/IL-17RA”).

One such preferred embodiment is described in FIGS. 4A and 4B, as wellas in SEQ ID NOs:157 and 158. This soluble polypeptide comprises exons1-6 of human IL-17RA (SEQ ID NO:21) and exons 8-16 of human IL-17RCx1(SEQ ID NO:2). More specifically, this soluble polypeptide is fused ifan Fc molecule, such as Fc5 as contained in SEQ ID Nos:157 and 158.However, one skilled in the art would easily recognize that any Fcmolecule can be utilized as well as any other molecule that would resultin dimerization.

As such, antagonists to IL-17F and IL-17A activity, such as IL-17RC andIL-17RC/IL-17RA soluble receptors of the present invention, are usefulin therapeutic treatment of inflammatory diseases, particularly asantagonists to both IL-17F and IL-17A singly or together in thetreatment of diseases involving these molecules. Moreover, antagoniststo IL-17A and IL-17F activity, such as the soluble receptors of thepresent invention, are useful in therapeutic treatment of otherinflammatory diseases for example as bind, block, inhibit, reduce,antagonize or neutralize IL-17F and IL-17A (either individually ortogether) in the treatment of psoriasis, atopic and contact dermatitis,IBD, IBS, colitis, endotoxemia, arthritis, rheumatoid arthritis,psoriatic arthritis, adult respiratory disease (ARD), septic shock,multiple organ failure, inflammatory lung injury such as asthma, chronicobstructive pulmonary disease (COPD), airway hyper-responsiveness,chronic bronchitis, allergic asthma, bacterial pneumonia, psoriasis,eczema, and inflammatory bowel disease such as ulcerative colitis andCrohn's disease, helicobacter pylori infection, intraabdominal adhesionsand/or abscesses as results of peritoneal inflammation (i.e. frominfection, injury, etc.), systemic lupus erythematosus (SLE), multiplesclerosis, systemic sclerosis, nephrotic syndrome, organ allograftrejection, graft vs. host disease (GVHD), kidney, lung, heart, etc.transplant rejection, streptococcal cell wall (SCW)-induced arthritis,osteoarthritis, gingivitis/periodontitis, herpetic stromal keratitis,cancers including prostate, renal, colon, ovarian, cervical, leukemia,angiogenesis, restenosis and Kawasaki disease.

Cytokine receptors subunits are characterized by a multi-domainstructure comprising a ligand-binding domain and an effector domain thatis typically involved in signal transduction. Multimeric cytokinereceptors include monomers, homodimers (e.g., PDGF receptor αα and ββisoforms, erythropoietin receptor, MPL [thrombopoietin receptor], andG-CSF receptor), heterodimers whose subunits each have ligand-bindingand effector domains (e.g., PDGF receptor αβ isoform), and multimershaving component subunits with disparate functions (e.g., IL-2, IL-3,IL-4, IL-5, IL-6, IL-7, and GM-CSF receptors). Some receptor subunitsare common to a plurality of receptors. For example, the AIC2B subunit,which cannot bind ligand on its own but includes an intracellular signaltransduction domain, is a component of IL-3 and GM-CSF receptors. Manycytokine receptors can be placed into one of four related families onthe basis of their structures and functions. Class I hematopoieticreceptors, for example, are characterized by the presence of a domaincontaining conserved cysteine residues and the WSXWS motif. Additionaldomains, including protein kinase domains; fibronectin type III domains;and immunoglobulin domains, which are characterized by disulfide-bondedloops, are present in certain hematopoietic receptors. Cytokine receptorstructure has been reviewed by Urdal, Ann. Reports Med. Chem.26:221-228, 1991 and Cosman, Cytokine 5:95-106, 1993. It is generallybelieved that under selective pressure for organisms to acquire newbiological functions, new receptor family members arose from duplicationof existing receptor genes leading to the existence of multi-genefamilies. Family members thus contain vestiges of the ancestral gene,and these characteristic features can be exploited in the isolation andidentification of additional family members.

Accordingly, the present invention is directed to Il-17A and IL-17Fantagonists that block each respective ligand from binding and/orsignaling through its corresponding receptor or receptors.

In preferred embodiments, such antagonists are based on IL-17RC'spolypeptide structure as depicted in FIGS. 1-4. The IL-17RC receptor hasa large number of splice variants based on the inclusion or exclusion ofspecific exons. As described below, some of these exons are required forligand (IL-17A and/or IL-17F) binding.

The present invention is based in part of the discovery of structuralsimilarity (“domains”) between IL-17RC and other members of the IL-17family, such as IL-17RA (SEQ ID NO:21). Specifically, three domains wereidentified:

1) Domain 1 (SEQ ID NOs: 159 and 160) comprises exons 8-10 of IL-17RC.This corresponds to IL-17RCx1's amino acid residues 193-276 of (SEQ IDNO:2) and IL-17RCx4's amino acid residues 208-291 of (SEQ ID NO:166).

2) Domain 2 (SEQ ID NOs: 161 and 162) comprises exons 11-13 of IL-17RC.This corresponds to IL-17RCx1's amino acid residues 277-370 of (SEQ IDNO:2) and IL-17RCx4's amino acid residues 292-385 of (SEQ ID NO:166).

3) Domain 3 (SEQ ID NOs: 163 and 164) comprises exons 14-16 of IL-17RC.This corresponds to IL-17RCx1's amino acid residues 371-447 of (SEQ IDNO:2) and IL-17RCx4's amino acid residues 386-462 of (SEQ ID NO:166).

Thus, the present invention is directed to soluble IL-17RC polypeptidesbased on different combinations of the exons depicted in FIG. 1.Specifically, examples of these soluble polypeptides include:

1) Variant 1210 (SEQ ID NOs: 67 and 68) which includes exons 1-6 and8-16 of human IL-17RCx1, fused to Fc10 (SEQ ID NOs: 174 and 175) via alinker (SEQ ID NOs: 176 and 177). Variant 1210 also has a pre-pro signalpeptide from otPA (polypeptide sequence shown in SEQ ID NO: 178). Fc5,or any equivalent known in the art, may also be used in place of Fc10.

2) Variant 1390 (SEQ ID NOs: 69 and 70) which includes exons 1-6 and8-16 of human IL-17RCx1, fused to Fc10 (SEQ ID NOs: 174 and 175).Variant 1390 also has the native signal sequence. Fc5, or any equivalentknown in the art, may also be used in place of Fc10.

3) Variant 1341 (SEQ ID NOs: 71 and 72) which includes exons 1-6 ofmurine IL-17RA and 8-16 of human IL-17RCx1, fused to Fc10 (SEQ ID NOs:174 and 175) via a linker (SEQ ID NOs: 176 and 177). Variant 1341 alsohas a signal peptide from murine IL-17RA (SEQ ID NO:181). Fc5, or anyequivalent known in the art, may also be used in place of Fc10.

4) Variant 1342 (SEQ ID NOs: 73 and 74) which includes exons 8-16 ofhuman IL-17RCx1, fused to Fc10 (SEQ ID NOs: 174 and 175) via a linker(SEQ ID NOs: 176 and 177). Variant 1342 also has a pre-pro signalpeptide from otPA (polypeptide sequence shown in SEQ ID NO: 178). Fc5,or any equivalent known in the art, may also be used in place of Fc10.

5) Variant 51 (SEQ ID NOs: 77 and 78) which includes exons 1-7 of humanIL-17RCx1, fused to Fc5 (SEQ ID NOs: 179 and 180). Variant 51 also hasthe native signal sequence. Fc10, or any equivalent known in the art,may also be used in place of Fc5.

6) Variant S2 (SEQ ID NOs: 81 and 82) which includes exons 1-8 of humanIL-17RCx1, fused to Fc5 (SEQ ID NOs: 179 and 180). Variant S2 also hasthe native signal sequence. Fc10, or any equivalent known in the art,may also be used in place of Fc5.

7) Variant S3 (SEQ ID NOs: 85 and 86) which includes exons 1-9 of humanIL-17RCx1, fused to Fc5 (SEQ ID NOs: 179 and 180). Variant S3 also hasthe native signal sequence. Fc10, or any equivalent known in the art,may also be used in place of Fc5.

8) Variant S4 (SEQ ID NOs: 89 and 90) which includes exons 1-10 of humanIL-17RCx1, fused to Fc5 (SEQ ID NOs: 179 and 180). Variant S4 also hasthe native signal sequence. Fc10, or any equivalent known in the art,may also be used in place of Fc5.

9) Variant S5 (SEQ ID NOs: 93 and 94) which includes exons 1-11 of humanIL-17RCx1, fused to Fc5 (SEQ ID NOs: 179 and 180). Variant S5 also hasthe native signal sequence. Fc10, or any equivalent known in the art,may also be used in place of Fc5.

10) Variant S6 (SEQ ID NOs: 97 and 98) which includes exons 14-16 ofhuman IL-17RCx1, fused to Fc5 (SEQ ID NOs: 179 and 180). Variant S6 alsohas the native signal sequence. Fc10, or any equivalent known in theart, may also be used in place of Fc5.

11) Variant S7 (SEQ ID NOs: 101 and 102) which includes exons 11-16 ofhuman IL-17RCx1, fused to Fc5 (SEQ ID NOs: 179 and 180). Variant S7 alsohas the native signal sequence. Fc10, or any equivalent known in theart, may also be used in place of Fc5.

12) Variant S10 (SEQ ID NOs: 105 and 106) which includes exons 7-16 ofhuman IL-17RCx1, fused to Fc5 (SEQ ID NOs: 179 and 180). Variant S10also has the native signal sequence. Fc10, or any equivalent known inthe art, may also be used in place of Fc5.

13) Variant S11 (SEQ ID NOs: 109 and 110) which includes exons 1-7 and14-16 of human IL-17RCx1, fused to Fc5 (SEQ ID NOs: 179 and 180).Variant S11 also has the native signal sequence. Fc10, or any equivalentknown in the art, may also be used in place of Fc5.

14) Variant S12 (SEQ ID NOs: 113 and 114) which includes exons 1-7 and11-16 of human IL-17RCx1, fused to Fc5 (SEQ ID NOs: 179 and 180).Variant S12 also has the native signal sequence. Fc10, or any equivalentknown in the art, may also be used in place of Fc5.

15) Variant S13 (SEQ ID NOs: 117 and 118) which includes exons 1-13 ofhuman IL-17RCx1 and exons 7-9 of human IL-17RA, fused to Fc5 (SEQ IDNOs: 179 and 180). Variant S13 also has the native signal sequence.Fc10, or any equivalent known in the art, may also be used in place ofFc5.

16) Variant S14 (SEQ ID NOs: 121 and 122) which includes exons 1-6 ofmurine IL-17RA, exons 8-13 of human IL-17RCx1 and exons 7-9 of murineIL-17RA, fused to Fc5 (SEQ ID NOs: 179 and 180). Variant S13 also hasthe native signal sequence. Fc10, or any equivalent known in the art,may also be used in place of Fc5.

17) Variant 1407 (SEQ ID NOs: 139 and 140) which includes exons 1-10 ofhuman IL-17RA and 8-16 of human IL-17RCx1, fused to Fc5 (SEQ ID NOs: 179and 180). Variant 1407 also has the native signal peptide from humanIL-17RA. Fc10, or any equivalent known in the art, may also be used inplace of Fc5.

18) Variant 1459 (SEQ ID NOs: 151 and 152) which includes exons 1-6 and8-16 of human IL-17RCx1, fused to Fc5 (SEQ ID NOs: 179 and 180) with aLeu21Ala substitution (as compared with IL-17RCx1). Variant 1459 alsohas a pre-pro signal peptide from otPA (polypeptide sequence shown inSEQ ID NO: 178). Fc10, or any equivalent known in the art, may also beused in place of Fc5.

19) Variant 1454 (SEQ ID NOs: 157 and 158) which includes exons 1-6 ofhuman IL-17RA and 8-16 of human IL-17RCx1, fused to Fc5 (SEQ ID NOs: 179and 180). Variant 1454 also has the native signal peptide from humanIL-17RA. Fc10, or any equivalent known in the art, may also be used inplace of Fc5. The mature form of variant 1454 polypeptide is shown inSEQ ID NO:183, which is encoded by the nucleic acid molecule of SEQ IDNO:182. Other secretory signal sequences may be substituted for thehuman IL-17RA signal sequence for expression in eukaryotic cells,including, for example, the human IL-17RC signal sequence (e.g., aminoacid residues 1-20 of SEQ ID NO:2), otPA pre-pro signal sequence (SEQ IDNO:178), human growth hormone signal sequence (SEQ ID NOs:168 and 169),and human CD33 signal sequence (SEQ ID NOs:172 and 173). Optionally, theC-terminal amino acid residue (residue 658 (Lys) of SEQ ID NO:183) iscleaved or deleted from variant 1454.

The above-described variants represent only a limited number of theembodiments of the present invention. One skilled in the art couldreadily, and without undue experimentation, design and test otherIL-17RC and/or IL-17RC/IL-17RA variants based on the teachings of thepresent application and in particular FIGS. 1-4 included herewith. Forinstance, other signal peptides which may be used in place of thosedisclosed above include: human growth hormone signal peptide (SEQ IDNOs: 168 and 169), murine immunoglobulin heavy chain variable region (VH26-10) (SEQ ID NOs: 170 and 171), or human CD33 (SEQ ID NOs: 172 and173).

Amongst other inventions, the present invention provides novel uses forthe soluble receptors of the present invention. These soluble receptorscan be based solely on IL-17RC (designated “IL-17RC,” “soluble IL-17RC,”or “sIL-17RC”, all of which may be used herein interchangeably), or canbe based on combining portions of IL-17RA with IL-17RC(“IL-17RC/IL-17RA,” “hybrid RC/RA,” “RC/RA,” “IL-17RA/RC,” or anyvariation thereof, for instance variant 1454, all of which may be usedherein interchangeably). The present invention also provides solubleIL-17RC and IL-17RC/IL-17RA polypeptide fragments and fusion proteins,for use in human inflammatory and autoimmune diseases. The solublereceptors of the present invention can be used to block, inhibit,reduce, antagonize or neutralize the activity of either IL-17F orIL-17A, or both IL-17A and IL-17F in the treatment of inflammation andinflammatory diseases such as psoriasis, psoriatic arthritis, rheumatoidarthritis, endotoxemia, IBD, IBS, colitis, asthma, allograft rejection,immune mediated renal diseases, hepatobiliary diseases, multiplesclerosis, atherosclerosis, promotion of tumor growth, or degenerativejoint disease and other inflammatory conditions disclosed herein.

An illustrative nucleotide sequence that encodes human IL-17RC(“IL-17RCx1”) is provided by SEQ ID NO:1; the encoded polypeptide isshown in SEQ ID NO:2. IL-17RC functions as a receptor for both IL-17A(SEQ ID NOs:13 and 14) and IL-17F (SEQ ID NOs:15 and 16). IL-17RC canact as a monomer, a homodimer or a heterodimer. Preferably, IL-17RC actsas a homodimeric receptor for both IL-17A and/or IL-17F. As described inthe present application, either the monomeric or the homodimericreceptor can comprise IL-17RC alone, or it may comprise portions ofother IL-17 family receptors, such as IL-17RA (“IL-17RC/IL-17RA”). Assuch, the present invention encompasses soluble receptors that compriseportions of IL-17RC in combination with IL-17RA, IL-17RE or any otherIL-17 family receptor. IL-17RC can also act as a heterodimeric receptorsubunit for a IL-17-related cytokine. For instance, IL-17RC may form aheterodimer with IL-17RA or another IL-17-like receptor. IL-17RC isdisclosed in commonly owned U.S. patent application Ser. No. 10/458,647,and commonly owned WIPO publication WO 01/04304, both of which areincorporated herein in their entirety by reference. Analysis of a humancDNA clone encoding IL-17RC (SEQ ID NO:1) revealed an open reading frameencoding 692 amino acids (SEQ ID NO:2) comprising a putative signalsequence of approximately 20 amino acid residues (amino acid residues 1to 20 of SEQ ID NO:2), an extracellular ligand-binding domain ofapproximately 431 amino acid residues (amino acid residues 21-452 of SEQID NO:2; SEQ ID NO:3), a transmembrane domain of approximately 20 aminoacid residues (amino acid residues 453-473 of SEQ ID NO:2), and anintracellular domain of approximately 203 amino acid residues (aminoacid residues 474 to 677 of SEQ ID NO:2). Furthermore, a ligand bindingdomain is represented by SEQ ID NO:22.

Yet another illustrative nucleotide sequence that encodes a varianthuman IL-17RC, designated as “IL-17RCx4” is provided by SEQ ID NO:165,the encoded polypeptide is shown in SEQ ID NO:166. The predicted signalpeptides is from residues 1-60 of SEQ ID NO:165 and 1-20 of SEQ IDNO:166; the extracellular domain from residues 61-1401 of SEQ ID NO:165and 21-467 of SEQ ID NO:166; the transmembrane domain is from residues1402-1464 of SEQ ID NO:165 and 468-488 of SEQ ID NO:166; and theintracellular domain is from residues 1465-2121 of SEQ ID NO:165 and489-707 of SEQ ID NO:166.

Yet another illustrative nucleotide sequence that encodes a varianthuman IL-17RC, designated as “IL-17RC-1” is provided by SEQ ID NO:4, theencoded polypeptide is shown in SEQ ID NO:5. IL-17RC-1 is disclosed incommonly owned U.S. patent application Ser. No. 10/458,647, and commonlyowned WIPO publication WO 01/04304, both of which are incorporatedherein in their entirety by reference. Sequence analysis revealed thatIL-17RC-1 is a truncated form of receptor polypeptide. That is,IL-17RC-1 lacks amino acid residues 1-113 of SEQ ID NO:2. SEQ ID NO:10presents an amino acid sequence of a IL-17RC-1 polypeptide that includesthe N-terminal portion of IL-17RC.

A comparison of the IL-17RC and IL-17RC-1 amino acid sequences alsoindicated that the two polypeptides represent alternatively splicedvariants. The amino acid sequence of IL-17RC includes a 17 amino acidsegment (amino acid residues 339 to 355 of SEQ ID NO:2), which IL-17RC-1lacks, while IL-17RC lacks, following amino acid 479, a 13 amino acidsegment found in IL-17RC-1 (amino acid residues 350 to 362 of SEQ IDNO:5). A polypeptide that contains both amino acid segments is providedby SEQ ID NO:11, whereas SEQ ID NO:12 presents the amino acid sequenceof a polypeptide that lacks both 13 and 17 amino acid segments.

Yet another illustrative nucleotide sequence that encodes a varianthuman IL-17RC, designated as “IL-17RC-6” is provided by SEQ ID NO:23,the encoded polypeptide is shown in SEQ ID NO:24. IL-17RC-6 contains a25 amino acid residue deletion as compared to IL-17RC as embodied in SEQID NO:2. Specifically, IL-17RC-6 does not contain amino acid residue 94to amino acid residue 118 of SEQ ID NO:2. Analysis of a human cDNA cloneencoding IL-17RC-6 (SEQ ID NO:23) revealed an extracellularligand-binding domain of approximately 427 amino acid residues (aminoacid residues 1-427 of SEQ ID NO:24), a transmembrane domain ofapproximately 20 amino acid residues (amino acid residues 428-448 of SEQID NO:24), and an intracellular domain of approximately 218 amino acidresidues (amino acid residues 449 to 667 of SEQ ID NO:24).

An illustrative nucleotide sequence that encodes a variant murineIL-17RC is provided by SEQ ID NO:25; the encoded polypeptide is shown inSEQ ID NO:26. Murine IL-17RC functions as a receptor for both murineIL-17A (SEQ ID NOs:17 and 18) and murine IL-17F (SEQ ID NOs:19 and 20).Analysis of a murine cDNA clone encoding IL-17RC (SEQ ID NO:25) revealedan extracellular ligand-binding domain of approximately 449 amino acidresidues SEQ ID NO:27). Furthermore, a ligand binding domain isrepresented by SEQ ID NO:28.

Yet another illustrative nucleotide sequence that encodes a variantmurine IL-17RC is provided by SEQ ID NO:29; the encoded polypeptide isshown in SEQ ID NO:30.

The IL-17RC gene resides in chromosome 3p25-3p24. As discussed below,this region is associated with various disorders and diseases.

Northern analyses indicate that there is strong expression of theIL-17RC gene in thyroid, adrenal gland, prostate, and liver tissues, andless expression in heart, small intestine, stomach, and trachea tissues.In contrast, there is little or no expression in brain, placenta, lung,skeletal muscle, kidney, pancreas, spleen, thymus, testis, ovary, colon,peripheral blood leukocytes, spinal cord, lymph node, and bone marrow.These observations show that IL-17RC sequences can be used differentiatebetween various tissues.

As described below, the present invention provides isolated polypeptidescomprising an amino acid sequence that is at least 70%, at least 80%, orat least 90%, or greater than 95%, such as 96%, 97%, 98%, or greaterthan 99% or more identical to a reference amino acid sequence of 21-692of SEQ ID NO:2, wherein the isolated polypeptide specifically binds withan antibody that specifically binds with a polypeptide comprising theamino acid sequence of SEQ ID NO:2. The present invention also providesisolated polypeptides comprising an amino acid sequence that is at least70%, at least 80%, or at least 90% identical to a reference amino acidsequence selected from the group consisting of: (a) amino acid residues21 to 452 of SEQ ID NO:2, (b) amino acid residues 21 to 435 of SEQ IDNO:10, (c) amino acid residues 21 to 677 of SEQ ID NO:2, and (d) aminoacid residues 1 to 692 of SEQ ID NO:2, wherein the isolated polypeptidespecifically binds with an antibody that specifically binds with apolypeptide consisting of either the amino acid sequence of SEQ ID NO:2,or the amino acid sequence of SEQ ID NO:10. Illustrative polypeptidesinclude a polypeptide comprising the amino acid sequence of SEQ ID NO:2,SEQ ID NO:10, SEQ ID NO:11, or SEQ ID NO:12.

The present invention also provides isolated polypeptides comprising anextracellular domain, wherein the extracellular domain comprises eitheramino acid residues 21 to 452 of the amino acid sequence of SEQ ID NO:2or amino acid residues 21 to 435 of the amino acid sequence of SEQ IDNO:10. Such polypeptides may further comprise a transmembrane domainthat resides in a carboxyl-terminal position relative to theextracellular domain, wherein the transmembrane domain comprises aminoacid residues 453 to 473 of SEQ ID NO:2. These polypeptides may alsocomprise an intracellular domain that resides in a carboxyl-terminalposition relative to the transmembrane domain, wherein the intracellulardomain comprises either amino acid residues 474 to 677 of SEQ ID NO:2,or amino acid residues 457 to 673 of SEQ ID NO:10, and optionally, asignal secretory sequence that resides in an amino-terminal positionrelative to the extracellular domain, wherein the signal secretorysequence comprises amino acid residues 1 to 20 of the amino acidsequence of SEQ ID NO:2.

The present invention also includes variant IL-17RC polypeptides,wherein the amino acid sequence of the variant polypeptide shares anidentity with the amino acid sequence of SEQ ID NO:2 selected from thegroup consisting of at least 70% identity, at least 80% identity, atleast 90% identity, at least 95% identity, or greater than 95% identity,and wherein any difference between the amino acid sequence of thevariant polypeptide and the amino acid sequence of SEQ ID NO:2 is due toone or more conservative amino acid substitutions.

Moreover, the present invention also provides isolated polypeptides asdisclosed above that bind IL-17F (e.g., human IL-17F polypeptidesequence as shown in SEQ ID NO:16). The human IL-17F polynucleotidesequence is shown in SEQ ID NO:15. The mouse IL-17F polynucleotidesequence is shown in SEQ ID NO:19, and corresponding polyepeptide isshown in SEQ ID NO:20. The present invention also provides isolatedpolypeptides as disclosed above that bind IL-17A (e.g., human IL-17Apolypeptide sequence as shown in SEQ ID NO:14). The human IL-17Apolynucleotide sequence is shown in SEQ ID NO:13. The mouse IL-17Apolynucleotide sequence is shown in SEQ ID NO:17, and correspondingpolyepeptide is shown in SEQ ID NO:18.

The present invention also provides isolated polypeptides and epitopescomprising at least 15 contiguous amino acid residues of an amino acidsequence of SEQ ID NO:2 or 3. Illustrative polypeptides includepolypeptides that either comprise, or consist of SEQ ID NO:2 or 3, anantigenic epitope thereof, or a functional IL-17A or IL-17F bindingfragment thereof. Moreover, the present invention also provides isolatedpolypeptides as disclosed above that bind to, block, inhibit, reduce,antagonize or neutralize the activity of IL-17F or IL-17A.

The present invention also includes variant IL-17RC polypeptides,wherein the amino acid sequence of the variant polypeptide shares anidentity with the amino acid residues of SEQ ID NO:2 selected from thegroup consisting of at least 70% identity, at least 80% identity, atleast 90% identity, at least 95% identity, or greater than 95% identity,such as 96%, 97%, 98%, or greater than 99% or more identity, and whereinany difference between the amino acid sequence of the variantpolypeptide and the corresponding amino acid sequence of SEQ ID NO:2 isdue to one or more conservative amino acid substitutions. Suchconservative amino acid substitutions are described herein. Moreover,the present invention also provides isolated polypeptides as disclosedabove that bind to, block, inhibit, reduce, antagonize or neutralize theactivity of IL-17F or IL-17A.

The present invention further provides pharmaceutical compositionscomprising a pharmaceutically acceptable carrier and at least one ofsuch an expression vector or recombinant virus comprising suchexpression vectors. The present invention further includespharmaceutical compositions, comprising a pharmaceutically acceptablecarrier and a polypeptide or antibody described herein.

The present invention also provides fusion proteins, comprising aIL-17RC polypeptide and an immunoglobulin moiety. In such fusionproteins, the immunoglobulin moiety may be an immunoglobulin heavy chainconstant region, such as a human F_(c) fragment. The present inventionfurther includes isolated nucleic acid molecules that encode such fusionproteins.

These and other aspects of the invention will become evident uponreference to the following detailed description. In addition, variousreferences are identified below and are incorporated by reference intheir entirety.

B) Definitions

In the description that follows, a number of terms are used extensively.The following definitions are provided to facilitate understanding ofthe invention.

As used herein, “nucleic acid” or “nucleic acid molecule” refers topolynucleotides, such as deoxyribonucleic acid (DNA) or ribonucleic acid(RNA), oligonucleotides, fragments generated by the polymerase chainreaction (PCR), and fragments generated by any of ligation, scission,endonuclease action, and exonuclease action. Nucleic acid molecules canbe composed of monomers that are naturally-occurring nucleotides (suchas DNA and RNA), or analogs of naturally-occurring nucleotides (e.g.,α-enantiomeric forms of naturally-occurring nucleotides), or acombination of both. Modified nucleotides can have alterations in sugarmoieties and/or in pyrimidine or purine base moieties. Sugarmodifications include, for example, replacement of one or more hydroxylgroups with halogens, alkyl groups, amines, and azido groups, or sugarscan be functionalized as ethers or esters. Moreover, the entire sugarmoiety can be replaced with sterically and electronically similarstructures, such as aza-sugars and carbocyclic sugar analogs. Examplesof modifications in a base moiety include alkylated purines andpyrimidines, acylated purines or pyrimidines, or other well-knownheterocyclic substitutes. Nucleic acid monomers can be linked byphosphodiester bonds or analogs of such linkages. Analogs ofphosphodiester linkages include phosphorothioate, phosphorodithioate,phosphoroselenoate, phosphorodiselenoate, phosphoroanilothioate,phosphoranilidate, phosphoramidate, and the like. The term “nucleic acidmolecule” also includes so-called “peptide nucleic acids,” whichcomprise naturally-occurring or modified nucleic acid bases attached toa polyamide backbone. Nucleic acids can be either single stranded ordouble stranded.

The term “complement of a nucleic acid molecule” refers to a nucleicacid molecule having a complementary nucleotide sequence and reverseorientation as compared to a reference nucleotide sequence. For example,the sequence 5′ ATGCACGGG 3′ is complementary to 5′ CCCGTGCAT 3′.

The term “degenerate nucleotide sequence” denotes a sequence ofnucleotides that includes one or more degenerate codons as compared to areference nucleic acid molecule that encodes a polypeptide. Degeneratecodons contain different triplets of nucleotides, but encode the sameamino acid residue (i.e., GAU and GAC triplets each encode Asp).

The term “structural gene” refers to a nucleic acid molecule that istranscribed into messenger RNA (mRNA), which is then translated into asequence of amino acids characteristic of a specific polypeptide.

An “isolated nucleic acid molecule” is a nucleic acid molecule that isnot integrated in the genomic DNA of an organism. For example, a DNAmolecule that encodes a growth factor that has been separated from thegenomic DNA of a cell is an isolated DNA molecule. Another example of anisolated nucleic acid molecule is a chemically-synthesized nucleic acidmolecule that is not integrated in the genome of an organism. A nucleicacid molecule that has been isolated from a particular species issmaller than the complete DNA molecule of a chromosome from thatspecies.

A “nucleic acid molecule construct” is a nucleic acid molecule, eithersingle- or double-stranded, that has been modified through humanintervention to contain segments of nucleic acid combined and juxtaposedin an arrangement not existing in nature.

“Linear DNA” denotes non-circular DNA molecules having free 5′ and 3′ends. Linear DNA can be prepared from closed circular DNA molecules,such as plasmids, by enzymatic digestion or physical disruption.

“Complementary DNA (cDNA)” is a single-stranded DNA molecule that isformed from an mRNA template by the enzyme reverse transcriptase.Typically, a primer complementary to portions of mRNA is employed forthe initiation of reverse transcription. Those skilled in the art alsouse the term “cDNA” to refer to a double-stranded DNA moleculeconsisting of such a single-stranded DNA molecule and its complementaryDNA strand. The term “cDNA” also refers to a clone of a cDNA moleculesynthesized from an RNA template.

A “promoter” is a nucleotide sequence that directs the transcription ofa structural gene. Typically, a promoter is located in the 5′ non-codingregion of a gene, proximal to the transcriptional start site of astructural gene. Sequence elements within promoters that function in theinitiation of transcription are often characterized by consensusnucleotide sequences. These promoter elements include RNA polymerasebinding sites, TATA sequences, CAAT sequences, differentiation-specificelements (DSEs; McGehee et al., Mol. Endocrinol. 7:551 (1993)), cyclicAMP response elements (CREs), serum response elements (SREs; Treisman,Seminars in Cancer Biol. 1:47 (1990)), glucocorticoid response elements(GREs), and binding sites for other transcription factors, such asCRE/ATF (O'Reilly et al., J. Biol. Chem. 267:19938 (1992)), AP2 (Ye etal., J. Biol. Chem. 269:25728 (1994)), SP1, cAMP response elementbinding protein (CREB; Loeken, Gene Expr. 3:253 (1993)) and octamerfactors (see, in general, Watson et al., eds., Molecular Biology of theGene, 4th ed. (The Benjamin/Cummings Publishing Company, Inc. 1987), andLemaigre and Rousseau, Biochem. J. 303:1 (1994)). If a promoter is aninducible promoter, then the rate of transcription increases in responseto an inducing agent. In contrast, the rate of transcription is notregulated by an inducing agent if the promoter is a constitutivepromoter. Repressible promoters are also known.

A “core promoter” contains essential nucleotide sequences for promoterfunction, including the TATA box and start of transcription. By thisdefinition, a core promoter may or may not have detectable activity inthe absence of specific sequences that may enhance the activity orconfer tissue specific activity.

A “regulatory element” is a nucleotide sequence that modulates theactivity of a core promoter. For example, a regulatory element maycontain a nucleotide sequence that binds with cellular factors enablingtranscription exclusively or preferentially in particular cells,tissues, or organelles. These types of regulatory elements are normallyassociated with genes that are expressed in a “cell-specific,”“tissue-specific,” or “organelle-specific” manner.

An “enhancer” is a type of regulatory element that can increase theefficiency of transcription, regardless of the distance or orientationof the enhancer relative to the start site of transcription.

“Heterologous DNA” refers to a DNA molecule, or a population of DNAmolecules, that does not exist naturally within a given host cell. DNAmolecules heterologous to a particular host cell may contain DNA derivedfrom the host cell species (i.e., endogenous DNA) so long as that hostDNA is combined with non-host DNA (i.e., exogenous DNA). For example, aDNA molecule containing a non-host DNA segment encoding a polypeptideoperably linked to a host DNA segment comprising a transcriptionpromoter is considered to be a heterologous DNA molecule. Conversely, aheterologous DNA molecule can comprise an endogenous gene operablylinked with an exogenous promoter. As another illustration, a DNAmolecule comprising a gene derived from a wild-type cell is consideredto be heterologous DNA if that DNA molecule is introduced into a mutantcell that lacks the wild-type gene.

A “polypeptide” is a polymer of amino acid residues joined by peptidebonds, whether produced naturally or synthetically. Polypeptides of lessthan about 10 amino acid residues are commonly referred to as“peptides.”

A “protein” is a macromolecule comprising one or more polypeptidechains.

A protein may also comprise non-peptidic components, such ascarbohydrate groups. Carbohydrates and other non-peptidic substituentsmay be added to a protein by the cell in which the protein is produced,and will vary with the type of cell. Proteins are defined herein interms of their amino acid backbone structures; substituents such ascarbohydrate groups are generally not specified, but may be presentnonetheless.

A peptide or polypeptide encoded by a non-host DNA molecule is a“heterologous” peptide or polypeptide.

A “cloning vector” is a nucleic acid molecule, such as a plasmid,cosmid, or bacteriophage, that has the capability of replicatingautonomously in a host cell. Cloning vectors typically contain one or asmall number of restriction endonuclease recognition sites that allowinsertion of a nucleic acid molecule in a determinable fashion withoutloss of an essential biological function of the vector, as well asnucleotide sequences encoding a marker gene that is suitable for use inthe identification and selection of cells transformed with the cloningvector. Marker genes typically include genes that provide tetracyclineresistance or ampicillin resistance.

An “expression vector” is a nucleic acid molecule encoding a gene thatis expressed in a host cell. Typically, an expression vector comprises atranscription promoter, a gene, and a transcription terminator. Geneexpression is usually placed under the control of a promoter, and such agene is said to be “operably linked to” the promoter. Similarly, aregulatory element and a core promoter are operably linked if theregulatory element modulates the activity of the core promoter.

A “recombinant host” is a cell that contains a heterologous nucleic acidmolecule, such as a cloning vector or expression vector. In the presentcontext, an example of a recombinant host is a cell that producesIL-17RC from an expression vector. In contrast, IL-17RC can be producedby a cell that is a “natural source” of IL-17RC, and that lacks anexpression vector.

“Integrative transformants” are recombinant host cells, in whichheterologous DNA has become integrated into the genomic DNA of thecells.

A “fusion protein” is a hybrid protein expressed by a nucleic acidmolecule comprising nucleotide sequences of at least two genes. Forexample, a fusion protein can comprise at least part of a IL-17RCpolypeptide fused with a polypeptide that binds an affinity matrix. Sucha fusion protein provides a means to isolate large quantities of IL-17RCusing affinity chromatography.

The term “receptor” denotes a cell-associated protein that binds to abioactive molecule termed a “ligand.” This interaction mediates theeffect of the ligand on the cell. Receptors can be membrane bound,cytosolic or nuclear; monomeric (e.g., thyroid stimulating hormonereceptor, beta-adrenergic receptor) or multimeric (e.g., PDGF receptor,growth hormone receptor, IL-3 receptor, GM-CSF receptor, G-CSF receptor,erythropoietin receptor and IL-6 receptor). Membrane-bound receptors arecharacterized by a multi-domain structure comprising an extracellularligand-binding domain and an intracellular effector domain that istypically involved in signal transduction. In certain membrane-boundreceptors, the extracellular ligand-binding domain and the intracellulareffector domain are located in separate polypeptides that comprise thecomplete functional receptor.

In general, the binding of ligand to receptor results in aconformational change in the receptor that causes an interaction betweenthe effector domain and other molecule(s) in the cell, which in turnleads to an alteration in the metabolism of the cell. Metabolic eventsthat are often linked to receptor-ligand interactions include genetranscription, phosphorylation, dephosphorylation, increases in cyclicAMP production, mobilization of cellular calcium, mobilization ofmembrane lipids, cell adhesion, hydrolysis of inositol lipids andhydrolysis of phospholipids.

A “soluble receptor” is a receptor polypeptide that is not bound to acell membrane. Soluble receptors are most commonly ligand-bindingreceptor polypeptides that lack transmembrane and cytoplasmic domains,and other linkage to the cell membrane such as via glycophosphoinositol(gpi). Soluble receptors can comprise additional amino acid residues,such as affinity tags that provide for purification of the polypeptideor provide sites for attachment of the polypeptide to a substrate, orimmunoglobulin constant region sequences. Many cell-surface receptorshave naturally occurring, soluble counterparts that are produced byproteolysis or translated from alternatively spliced mRNAs. Solublereceptors can be monomeric, homodimeric, heterodimeric, or multimeric,with multimeric receptors generally not comprising more than 9 subunits,preferably not comprising more than 6 subunits, and most preferably notcomprising more than 3 subunits. Receptor polypeptides are said to besubstantially free of transmembrane and intracellular polypeptidesegments when they lack sufficient portions of these segments to providemembrane anchoring or signal transduction, respectively. Solublereceptors of cytokine receptors generally comprise the extracellularcytokine binding domain free of a transmembrane domain and intracellulardomain. For example, representative soluble receptors include solublereceptors for IL-17RA as shown in SEQ ID NOs: 167 (polynucleotide) and21 (polypeptide). It is well within the level of one of skill in the artto delineate what sequences of a known cytokine receptor sequencecomprise the extracellular cytokine binding domain free of atransmembrane domain and intracellular domain. Moreover, one of skill inthe art using the genetic code can readily determine polynucleotidesthat encode such soluble receptor polypeptides.

The term “secretory signal sequence” denotes a DNA sequence that encodesa peptide (a “secretory peptide”) that, as a component of a largerpolypeptide, directs the larger polypeptide through a secretory pathwayof a cell in which it is synthesized. The larger polypeptide is commonlycleaved to remove the secretory peptide during transit through thesecretory pathway.

An “isolated polypeptide” is a polypeptide that is essentially free fromcontaminating cellular components, such as carbohydrate, lipid, or otherproteinaceous impurities associated with the polypeptide in nature.Typically, a preparation of isolated polypeptide contains thepolypeptide in a highly purified form, i.e., at least about 80% pure, atleast about 90% pure, at least about 95% pure, greater than 95% pure,such as 96%, 97%, or 98% or more pure, or greater than 99% pure. One wayto show that a particular protein preparation contains an isolatedpolypeptide is by the appearance of a single band following sodiumdodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of the proteinpreparation and Coomassie Brilliant Blue staining of the gel. However,the term “isolated” does not exclude the presence of the samepolypeptide in alternative physical forms, such as dimers oralternatively glycosylated or derivatized forms.

The terms “amino-terminal” and “carboxyl-terminal” are used herein todenote positions within polypeptides. Where the context allows, theseterms are used with reference to a particular sequence or portion of apolypeptide to denote proximity or relative position. For example, acertain sequence positioned carboxyl-terminal to a reference sequencewithin a polypeptide is located proximal to the carboxyl terminus of thereference sequence, but is not necessarily at the carboxyl terminus ofthe complete polypeptide.

The term “expression” refers to the biosynthesis of a gene product. Forexample, in the case of a structural gene, expression involvestranscription of the structural gene into mRNA and the translation ofmRNA into one or more polypeptides.

The term “splice variant” is used herein to denote alternative forms ofRNA transcribed from a gene. Splice variation arises naturally throughuse of alternative splicing sites within a transcribed RNA molecule, orless commonly between separately transcribed RNA molecules, and mayresult in several mRNAs transcribed from the same gene. Splice variantsmay encode polypeptides having altered amino acid sequence. The termsplice variant is also used herein to denote a polypeptide encoded by asplice variant of an mRNA transcribed from a gene.

As used herein, the term “immunomodulator” includes cytokines, stem cellgrowth factors, lymphotoxins, co-stimulatory molecules, hematopoieticfactors, and the like, and synthetic analogs of these molecules.

The term “complement/anti-complement pair” denotes non-identicalmoieties that form a non-covalently associated, stable pair underappropriate conditions. For instance, biotin and avidin (orstreptavidin) are prototypical members of a complement/anti-complementpair. Other exemplary complement/anti-complement pairs includereceptor/ligand pairs, antibody/antigen (or hapten or epitope) pairs,sense/antisense polynucleotide pairs, and the like. Where subsequentdissociation of the complement/anti-complement pair is desirable, thecomplement/anti-complement pair preferably has a binding affinity ofless than 10⁹ M⁻¹.

An “anti-idiotype antibody” is an antibody that binds with the variableregion domain of an immunoglobulin. In the present context, ananti-idiotype antibody binds with the variable region of an anti-IL-17RCantibody, and thus, an anti-idiotype antibody mimics an epitope ofIL-17RC.

An “antibody fragment” is a portion of an antibody such as F(ab′)₂,F(ab)₂, Fab′, Fab, and the like. Regardless of structure, an antibodyfragment binds with the same antigen that is recognized by the intactantibody. For example, an anti-IL-17RC monoclonal antibody fragmentbinds with an epitope of IL-17RC.

The term “antibody fragment” also includes a synthetic or a geneticallyengineered polypeptide that binds to a specific antigen, such aspolypeptides consisting of the light chain variable region, “Fv”fragments consisting of the variable regions of the heavy and lightchains, recombinant single chain polypeptide molecules in which lightand heavy variable regions are connected by a peptide linker (“scFvproteins”), and minimal recognition units consisting of the amino acidresidues that mimic the hypervariable region.

A “chimeric antibody” is a recombinant protein that contains thevariable domains and complementary determining regions derived from arodent antibody, while the remainder of the antibody molecule is derivedfrom a human antibody.

“Humanized antibodies” are recombinant proteins in which murinecomplementarity determining regions of a monoclonal antibody have beentransferred from heavy and light variable chains of the murineimmunoglobulin into a human variable domain. Construction of humanizedantibodies for therapeutic use in humans that are derived from murineantibodies, such as those that bind to or neutralize a human protein, iswithin the skill of one in the art.

As used herein, a “therapeutic agent” is a molecule or atom which isconjugated to an antibody moiety to produce a conjugate which is usefulfor therapy. Examples of therapeutic agents include drugs, toxins,immunomodulators, chelators, boron compounds, photoactive agents ordyes, and radioisotopes.

A “detectable label” is a molecule or atom which can be conjugated to anantibody moiety to produce a molecule useful for diagnosis. Examples ofdetectable labels include chelators, photoactive agents, radioisotopes,fluorescent agents, paramagnetic ions, or other marker moieties.

The term “affinity tag” is used herein to denote a polypeptide segmentthat can be attached to a second polypeptide to provide for purificationor detection of the second polypeptide or provide sites for attachmentof the second polypeptide to a substrate. In principal, any peptide orprotein for which an antibody or other specific binding agent isavailable can be used as an affinity tag. Affinity tags include apoly-histidine tract, protein A (Nilsson et al., EMBO J. 4:1075 (1985);Nilsson et al., Methods Enzymol. 198:3 (1991)), glutathione Stransferase (Smith and Johnson, Gene 67:31 (1988)), Glu-Glu affinity tag(Grussenmeyer et al., Proc. Natl. Acad. Sci. USA 82:7952 (1985)),substance P, FLAG peptide (Hopp et al., Biotechnology 6:1204 (1988)),streptavidin binding peptide, or other antigenic epitope or bindingdomain. See generally Ford et al., Protein Expression and Purification2:95 (1991). DNA molecules encoding affinity tags are available fromcommercial suppliers (e.g., Pharmacia Biotech, Piscataway, N.J.).

A “naked antibody” is an entire antibody, as opposed to an antibodyfragment, which is not conjugated with a therapeutic agent. Nakedantibodies include both polyclonal and monoclonal antibodies, as well ascertain recombinant antibodies, such as chimeric and humanizedantibodies.

As used herein, the term “antibody component” includes both an entireantibody and an antibody fragment.

An “immunoconjugate” is a conjugate of an antibody component with atherapeutic agent or a detectable label.

As used herein, the term “antibody fusion protein” refers to arecombinant molecule that comprises an antibody component and a IL-17RCpolypeptide component. Examples of an antibody fusion protein include aprotein that comprises a IL-17RC extracellular domain, and either an Fcdomain or an antigen-binding region.

A “target polypeptide” or a “target peptide” is an amino acid sequencethat comprises at least one epitope, and that is expressed on a targetcell, such as a tumor cell, or a cell that carries an infectious agentantigen. T cells recognize peptide epitopes presented by a majorhistocompatibility complex molecule to a target polypeptide or targetpeptide and typically lyse the target cell or recruit other immune cellsto the site of the target cell, thereby killing the target cell.

An “antigenic peptide” is a peptide which will bind a majorhistocompatibility complex molecule to form an MHC-peptide complex whichis recognized by a T cell, thereby inducing a cytotoxic lymphocyteresponse upon presentation to the T cell. Thus, antigenic peptides arecapable of binding to an appropriate major histocompatibility complexmolecule and inducing a cytotoxic T cells response, such as cell lysisor specific cytokine release against the target cell which binds orexpresses the antigen. The antigenic peptide can be bound in the contextof a class I or class II major histocompatibility complex molecule, onan antigen presenting cell or on a target cell.

In eukaryotes, RNA polymerase II catalyzes the transcription of astructural gene to produce mRNA. A nucleic acid molecule can be designedto contain an RNA polymerase II template in which the RNA transcript hasa sequence that is complementary to that of a specific mRNA. The RNAtranscript is termed an “anti-sense RNA” and a nucleic acid moleculethat encodes the anti-sense RNA is termed an “anti-sense gene.”Anti-sense RNA molecules are capable of binding to mRNA molecules,resulting in an inhibition of mRNA translation.

An “anti-sense oligonucleotide specific for IL-17RC” or a “IL-17RCanti-sense oligonucleotide” is an oligonucleotide having a sequence (a)capable of forming a stable triplex with a portion of the IL-17RC gene,or (b) capable of forming a stable duplex with a portion of an mRNAtranscript of the IL-17RC gene.

A “ribozyme” is a nucleic acid molecule that contains a catalyticcenter. The term includes RNA enzymes, self-splicing RNAs, self-cleavingRNAs, and nucleic acid molecules that perform these catalytic functions.A nucleic acid molecule that encodes a ribozyme is termed a “ribozymegene.”

An “external guide sequence” is a nucleic acid molecule that directs theendogenous ribozyme, RNase P, to a particular species of intracellularmRNA, resulting in the cleavage of the mRNA by RNase P. A nucleic acidmolecule that encodes an external guide sequence is termed an “externalguide sequence gene.”

The term “variant IL-17RC gene” refers to nucleic acid molecules thatencode a polypeptide having an amino acid sequence that is amodification of SEQ ID NO:2. Such variants include naturally-occurringpolymorphisms of IL-17RC genes, as well as synthetic genes that containconservative amino acid substitutions of the amino acid sequence of SEQID NO:2. Additional variant forms of IL-17RC genes are nucleic acidmolecules that contain insertions or deletions of the nucleotidesequences described herein. A variant IL-17RC gene can be identified,for example, by determining whether the gene hybridizes with a nucleicacid molecule having the nucleotide sequence of SEQ ID NO:10R SEQ IDNO:4, or its complement, under stringent conditions.

Alternatively, variant IL-17RC genes can be identified by sequencecomparison. Two amino acid sequences have “100% amino acid sequenceidentity” if the amino acid residues of the two amino acid sequences arethe same when aligned for maximal correspondence. Similarly, twonucleotide sequences have “100% nucleotide sequence identity” if thenucleotide residues of the two nucleotide sequences are the same whenaligned for maximal correspondence. Sequence comparisons can beperformed using standard software programs such as those included in theLASERGENE bioinformatics computing suite, which is produced by DNASTAR(Madison, Wis.). Other methods for comparing two nucleotide or aminoacid sequences by determining optimal alignment are well-known to thoseof skill in the art (see, for example, Peruski and Peruski, The Internetand the New Biology: Tools for Genomic and Molecular Research (ASMPress, Inc. 1997), Wu et al. (eds.), “Information Superhighway andComputer Databases of Nucleic Acids and Proteins,” in Methods in GeneBiotechnology, pages 123-151 (CRC Press, Inc. 1997), and Bishop (ed.),Guide to Human Genome Computing, 2nd Edition (Academic Press, Inc.1998)). Particular methods for determining sequence identity aredescribed below.

Regardless of the particular method used to identify a variant IL-17RCgene or variant IL-17RC polypeptide, a variant gene or polypeptideencoded by a variant gene may be functionally characterized the abilityto bind specifically to an anti-IL-17RC antibody. A variant IL-17RC geneor variant IL-17RC polypeptide may also be functionally characterizedthe ability to bind to its ligand, for example, IL-17A and/or IL-17F,using a biological or biochemical assay described herein.

The term “allelic variant” is used herein to denote any of two or morealternative forms of a gene occupying the same chromosomal locus.Allelic variation arises naturally through mutation, and may result inphenotypic polymorphism within populations. Gene mutations can be silent(no change in the encoded polypeptide) or may encode polypeptides havingaltered amino acid sequence. The term allelic variant is also usedherein to denote a protein encoded by an allelic variant of a gene.

The term “ortholog” denotes a polypeptide or protein obtained from onespecies that is the functional counterpart of a polypeptide or proteinfrom a different species. Sequence differences among orthologs are theresult of speciation.

“Paralogs” are distinct but structurally related proteins made by anorganism. Paralogs are believed to arise through gene duplication. Forexample, α-globin, β-globin, and myoglobin are paralogs of each other.

The present invention includes functional fragments of IL-17RC genes.Within the context of this invention, a “functional fragment” of aIL-17RC gene refers to a nucleic acid molecule that encodes a portion ofa IL-17RC polypeptide which is a domain described herein or at leastspecifically binds with an anti-IL-17RC antibody.

Due to the imprecision of standard analytical methods, molecular weightsand lengths of polymers are understood to be approximate values. Whensuch a value is expressed as “about” X or “approximately” X, the statedvalue of X will be understood to be accurate to ±10%.

C) Production of IL-17RA and IL-17RC Polynucleotides or Genes

Nucleic acid molecules encoding a human IL-17RA or IL-17RC gene orpolynucleotides encoding any of the soluble polypeptides of the presentinvention can be obtained by screening a human cDNA or genomic libraryusing polynucleotide probes based upon SEQ ID NO:1, SEQ ID NO:4. Thesetechniques are standard and well-established, and may be accomplishedusing cloning kits available by commercial suppliers. See, for example,Ausubel et al. (eds.), Short Protocols in Molecular Biology, 3^(rd)Edition, John Wiley & Sons 1995; Wu et al., Methods in GeneBiotechnology, CRC Press, Inc. 1997; Aviv and Leder, Proc. Nat'l Acad.Sci. USA 69:1408 (1972); Huynh et al., “Constructing and Screening cDNALibraries in λgt10 and λgt11,” in DNA Cloning: A Practical Approach Vol.I, Glover (ed.), page 49 (IRL Press, 1985); Wu (1997) at pages 47-52.

Nucleic acid molecules that encode a human IL-17RA or IL-17RC gene canalso be obtained using the polymerase chain reaction (PCR) witholigonucleotide primers having nucleotide sequences that are based uponthe nucleotide sequences of the IL-17RA or IL-17RC gene or cDNA. Generalmethods for screening libraries with PCR are provided by, for example,Yu et al., “Use of the Polymerase Chain Reaction to Screen PhageLibraries,” in Methods in Molecular Biology, Vol. 15: PCR Protocols:Current Methods and Applications, White (ed.), Humana Press, Inc., 1993.Moreover, techniques for using PCR to isolate related genes aredescribed by, for example, Preston, “Use of Degenerate OligonucleotidePrimers and the Polymerase Chain Reaction to Clone Gene Family Members,”in Methods in Molecular Biology, Vol. 15: PCR Protocols: Current Methodsand Applications, White (ed.), Humana Press, Inc. 1993. As analternative, an IL-17RA or IL-17RC gene can be obtained by synthesizingnucleic acid molecules using mutually priming long oligonucleotides andthe nucleotide sequences described herein (see, for example, Ausubel(1995)). Established techniques using the polymerase chain reactionprovide the ability to synthesize DNA molecules at least two kilobasesin length (Adang et al., Plant Molec. Biol. 21:1131 (1993), Bambot etal., PCR Methods and Applications 2:266 (1993), Dillon et al., “Use ofthe Polymerase Chain Reaction for the Rapid Construction of SyntheticGenes,” in Methods in Molecular Biology, Vol. 15: PCR Protocols: CurrentMethods and Applications, White (ed.), pages 263-268, (Humana Press,Inc. 1993), and Holowachuk et al., PCR Methods Appl. 4:299 (1995)). Forreviews on polynucleotide synthesis, see, for example, Glick andPasternak, Molecular Biotechnology, Principles and Applications ofRecombinant DNA (ASM Press 1994), Itakura et al., Annu. Rev. Biochem.53:323 (1984), and Climie et al., Proc. Nat'l Acad. Sci. USA 87:633(1990).

D) Production of IL-17RA or IL-17RC Gene Variants

The present invention provides a variety of nucleic acid molecules,including DNA and RNA molecules, that encode the IL-17RA or IL-17RCpolypeptides disclosed herein. Those skilled in the art will readilyrecognize that, in view of the degeneracy of the genetic code,considerable sequence variation is possible among these polynucleotidemolecules. Moreover, the present invention also provides isolatedsoluble monomeric, homodimeric, heterodimeric and multimeric receptorpolypeptides that comprise at least a portion of IL-17RC that issubstantially homologous to the receptor polypeptide of SEQ ID NO:2.Thus, the present invention contemplates IL-17RA or IL-17RCpolypeptide-encoding nucleic acid molecules comprising degeneratenucleotides of SEQ ID NO:1 or SEQ ID NO:4, and their RNA equivalents.

Those skilled in the art will readily recognize that, in view of thedegeneracy of the genetic code, considerable sequence variation ispossible among these polynucleotide molecules. SEQ ID NO:7 is adegenerate nucleotide sequence that encompasses all nucleic acidmolecules that encode the IL-17RC polypeptide of SEQ ID NO:2. Thoseskilled in the art will recognize that the degenerate sequence of SEQ IDNO:7 also provides all RNA sequences encoding SEQ ID NO:2, bysubstituting U for T. Thus, the present invention contemplates IL-17RCpolypeptide-encoding nucleic acid molecules comprising nucleotide 154 tonucleotide 2229 of SEQ ID NO:1, and their RNA equivalents. Similarly,the IL-17RC-1 degenerate sequence of SEQ ID NO:6 also provides all RNAsequences encoding SEQ ID NO:5, by substituting U for T.

Table 4 sets forth the one-letter codes to denote degenerate nucleotidepositions. “Resolutions” are the nucleotides denoted by a code letter.“Complement” indicates the code for the complementary nucleotide(s). Forexample, the code Y denotes either C or T, and its complement R denotesA or G, A being complementary to T, and G being complementary to C.

TABLE 4 Nucleotide Resolution Complement Resolution A A T T C C G G G GC C T T A A R A|G Y C|T Y C|T R A|G M A|C K G|T K G|T M A|C S C|G S C|GW A|T W A|T H A|C|T D A|G|T B C|G|T V A|C|G V A|C|G B C|G|T D A|G|T HA|C|T N A|C|G|T N A|C|G|T

The degenerate codons, encompassing all possible codons for a givenamino acid, are set forth in Table 5.

TABLE 5 One Amino Letter Degenerate Acid Code Codons Codon Cys C TGC TGTTGY Ser S AGC AGT TCA TCC TCG TCT WSN Thr T ACA ACC ACG ACT ACN Pro PCCA CCC CCG CCT CCN Ala A GCA GCC GCG GCT GCN Gly G GGA GGC GGG GGT GGNAsn N AAC AAT AAY Asp D GAC GAT GAY Glu E GAA GAG GAR Gln Q CAA CAG CARHis H CAC CAT CAY Arg R AGA AGG CGA CGC CGG CGT MGN Lys K AAA AAG AARMet M ATG ATG Ile I ATA ATC ATT ATH Leu L CTA CTC CTG CTT TTA TTG YTNVal V GTA GTC GTG GTT GTN Phe F TTC TTT TTY Tyr Y TAC TAT TAY Trp W TGGTGG Ter • TAA TAG TGA TRR Asn|Asp B RAY Glu|Gln Z SAR Any X NNN

One of ordinary skill in the art will appreciate that some ambiguity isintroduced in determining a degenerate codon, representative of allpossible codons encoding an amino acid. For example, the degeneratecodon for serine (WSN) can, in some circumstances, encode arginine(AGR), and the degenerate codon for arginine (MGN) can, in somecircumstances, encode serine (AGY). A similar relationship existsbetween codons encoding phenylalanine and leucine. Thus, somepolynucleotides encompassed by the degenerate sequence may encodevariant amino acid sequences, but one of ordinary skill in the art caneasily identify such variant sequences by reference to the amino acidsequences of SEQ ID NO:6. Variant sequences can be readily tested forfunctionality as described herein.

Different species can exhibit “preferential codon usage.” In general,see, Grantham et al., Nucl. Acids Res. 8:1893 (1980), Haas et al. Curr.Biol. 6:315 (1996), Wain-Hobson et al., Gene 13:355 (1981), Grosjean andFiers, Gene 18:199 (1982), Holm, Nuc. Acids Res. 14:3075 (1986),Ikemura, J. Mol. Biol. 158:573 (1982), Sharp and Matassi, Curr. Opin.Genet. Dev. 4:851 (1994), Kane, Curr. Opin. Biotechnol. 6:494 (1995),and Makrides, Microbiol. Rev. 60:512 (1996). As used herein, the term“preferential codon usage” or “preferential codons” is a term of artreferring to protein translation codons that are most frequently used incells of a certain species, thus favoring one or a few representativesof the possible codons encoding each amino acid (See Table 5). Forexample, the amino acid threonine (Thr) may be encoded by ACA, ACC, ACG,or ACT, but in mammalian cells ACC is the most commonly used codon; inother species, for example, insect cells, yeast, viruses or bacteria,different Thr codons may be preferential. Preferential codons for aparticular species can be introduced into the polynucleotides of thepresent invention by a variety of methods known in the art. Introductionof preferential codon sequences into recombinant DNA can, for example,enhance production of the protein by making protein translation moreefficient within a particular cell type or species. Therefore, thedegenerate codon sequences disclosed herein serve as a template foroptimizing expression of polynucleotides in various cell types andspecies commonly used in the art and disclosed herein. Sequencescontaining preferential codons can be tested and optimized forexpression in various species, and tested for functionality as disclosedherein.

An IL-17RA or IL-17RC-encoding cDNA can be isolated by a variety ofmethods, such as by probing with a complete or partial human cDNA orwith one or more sets of degenerate probes based on the disclosedsequences. A cDNA can also be cloned using the polymerase chain reactionwith primers designed from the representative human IL-17RA or IL-17RCsequences disclosed herein. In addition, a cDNA library can be used totransform or transfect host cells, and expression of the cDNA ofinterest can be detected with an antibody to IL-17RA or IL-17RCpolypeptide.

Those skilled in the art will recognize that the sequence disclosed inSEQ ID NO:1 represents a single allele of human IL-17RC, and thatallelic variation and alternative splicing are expected to occur.Allelic variants of this sequence can be cloned by probing cDNA orgenomic libraries from different individuals according to standardprocedures. Allelic variants of the nucleotide sequences disclosedherein, including those containing silent mutations and those in whichmutations result in amino acid sequence changes, are within the scope ofthe present invention, as are proteins which are allelic variants of theamino acid sequences disclosed herein. cDNA molecules generated fromalternatively spliced mRNAs, which retain the properties of the IL-17RCpolypeptide are included within the scope of the present invention, asare polypeptides encoded by such cDNAs and mRNAs. Allelic variants andsplice variants of these sequences can be cloned by probing cDNA orgenomic libraries from different individuals or tissues according tostandard procedures known in the art.

Using the methods discussed above, one of ordinary skill in the art canprepare a variety of polypeptides encoding a soluble receptor thatcomprises a portion of an IL-17RC receptor subunit that is substantiallyhomologous to either SEQ ID NO:1 or SEQ ID NO:4, or that encodes all ofor a fragment of SEQ ID NO:2 or SEQ ID NO:5, or allelic variants thereofand retain the ligand-binding properties of the wild-type IL-17RCreceptor. Such polypeptides may also include additional polypeptidesegments as generally disclosed herein.

Within certain embodiments of the invention, the isolated nucleic acidmolecules can hybridize under stringent conditions to nucleic acidmolecules comprising nucleotide sequences disclosed herein. For example,such nucleic acid molecules can hybridize under stringent conditions tonucleic acid molecules comprising the nucleotide sequence of SEQ IDNO:10R SEQ ID NO:4, or to nucleic acid molecules comprising a nucleotidesequence complementary to SEQ ID NO:10R SEQ ID NO:4, or fragmentsthereof.

In general, stringent conditions are selected to be about 5° C. lowerthan the thermal melting point (T_(m)) for the specific sequence at adefined ionic strength and pH. The T_(m) is the temperature (underdefined ionic strength and pH) at which 50% of the target sequencehybridizes to a perfectly matched probe. Following hybridization, thenucleic acid molecules can be washed to remove non-hybridized nucleicacid molecules under stringent conditions, or under highly stringentconditions. See, for example, Sambrook et al., Molecular Cloning: ALaboratory Manual, Second Edition (Cold Spring Harbor Press 1989);Ausubel et al., (eds.), Current Protocols in Molecular Biology (JohnWiley and Sons, Inc. 1987); Berger and Kimmel (eds.), Guide to MolecularCloning Techniques, (Academic Press, Inc. 1987); and Wetmur, Crit. Rev.Biochem. Mol. Biol. 26:227 (1990)). Sequence analysis software such asOLIGO 6.0 (LSR; Long Lake, Minn.) and Primer Premier 4.0 (PremierBiosoft International; Palo Alto, Calif.), as well as sites on theInternet, are available tools for analyzing a given sequence andcalculating T_(m) based on user-defined criteria. It is well within theabilities of one skilled in the art to adapthybridization and washconditions for use with a particular polynucleotide hybrid.

The present invention also provides for isolated IL-17RA or IL-17RCpolypeptides that have a substantially similar sequence identity to thepolypeptides of SEQ ID NO:2 (IL-17RC) and SEQ ID NO:21 (IL-17RA), ortheir orthologs. The term “substantially similar sequence identity” isused herein to denote polypeptides having at least 70%, at least 80%, atleast 90%, at least 95%, such as 96%, 97%, 98%, or greater than 95%sequence identity to the sequences shown in SEQ ID NO:2, or theirorthologs. For example, variant and orthologous IL-17RA or IL-17RCreceptors can be used to generate an immune response and raisecross-reactive antibodies to human IL-17RA or IL-17RC. Such antibodiescan be humanized, and modified as described herein, and usedtherapeutically to treat psoriasis, psoriatic arthritis, IBD, IBS,colitis, endotoxemia as well as in other therapeutic applicationsdescribed herein.

The present invention also contemplates IL-17RA or IL-17RC orIL-17RC/IL-17RA variant nucleic acid molecules that can be identifiedusing two criteria: a determination of the similarity between theencoded polypeptide with any amino acid sequence as described herein,such as the amino acid sequence of SEQ ID NO:2 (IL-17RC), SEQ ID NO:21(IL-17RA) or SEQ ID NOs:158 and 183 (IL-17RC/IL-17RA), and ahybridization assay. Such variants include nucleic acid molecules (1)that remain hybridized with a nucleic acid molecule having a nucleotidesequence as described herein, such as the nucleotide sequence of SEQ IDNO:1 or SEQ ID NO:4 for IL-17RC (or its full-length complement) or SEQID NO:157 for IL-17RC/IL-17RA (or its full-length complement) understringent washing conditions, in which the wash stringency is equivalentto 0.5×-2×SSC with 0.1% SDS at 55-65° C., and (2) that encode apolypeptide having at least 70%, at least 80%, at least 90%, at least95%, or greater than 95% such as 96%, 97%, 98%, or 99%, sequenceidentity to an amino acid sequence as described herein, such as theamino acid sequence of SEQ ID NO:2 and SEQ ID NO:158. Alternatively,IL-17RC variants can be characterized as nucleic acid molecules (1) thatremain hybridized with a nucleic acid molecule as described herein, suchas the nucleotide sequence of SEQ ID NO:10R SEQ ID NO:4 (or its fulllength complement) or of SEQ ID NO:157 (or its full-length complement)under highly stringent washing conditions, in which the wash stringencyis equivalent to 0.1×-0.2×SSC with 0.1% SDS at 50-65° C., and (2) thatencode a polypeptide having at least 70%, at least 80%, at least 90%, atleast 95% or greater than 95%, such as 96%, 97%, 98%, or 99% or greater,sequence identity to an amino acid sequence as described herein, such asthe amino acid sequence of SEQ ID NO:2 and SEQ ID NO:158.

The present invention provides, for example, an isolated polypeptidecomprising an amino acid sequence having at least 85%, at least 86%, atleast 87%, at least 88%, at least 89%, at least 90%, at least 91%, atleast 92%, at least 93%, at least 94%, at least 95%, at least 96%, atleast 97%, at least 98%, at least 99%, and at least 99.5% sequenceidentity with amino acid residues 200-458 of SEQ ID NO:158 (whichincludes exons 8-16 of IL-17RC), or amino acid residues 33-458 of SEQ IDNO:158 (which includes exons 1-6 of IL-17A and 8-16 of IL-17RC), oramino acid residues 1-458 of SEQ ID NO:158, or amino acid residues33-690 of SEQ ID NO:158 or amino acid residues 1-690 of SEQ ID NO:158,wherein the polypeptide binds IL-17A and/or IL-17F. The polypeptides canalso be used to bind, block, reduce, antagonize or neutralize IL-17Aand/or IL-17F in the treatment of psoriasis, atopic and contactdermatitis, IBD, IBS, colitis, endotoxemia, arthritis, rheumatoidarthritis, Lyme disease arthritis, psoriatic arthritis, adultrespiratory disease (ARD), septic shock, multiple organ failure,inflammatory lung injury such as asthma, chronic obstructive pulmonarydisease (COPD), airway hyper-responsiveness, chronic bronchitis,allergic asthma, bacterial pneumonia, psoriasis, eczema, andinflammatory bowel disease such as ulcerative colitis and Crohn'sdisease, helicobacter pylori infection, intraabdominal adhesions and/orabscesses as results of peritoneal inflammation (i.e. from infection,injury, etc.), systemic lupus erythematosus (SLE), lupus nephritis,Diabetes Type I, coronary artery disease, stroke, multiple sclerosis,systemic sclerosis, scleroderma, nephrotic syndrome, sepsis, organallograft rejection, graft vs. host disease (GVHD), transplant rejection(e.g., kidney, lung, and heart), streptococcal cell wall (SCW)-inducedarthritis, osteoarthritis, gingivitis/periodontitis, herpetic stromalkeratitis, osteoporosis, neuritis, cancers including prostate, renal,colon, ovarian, cervical, leukemia, cancer angiogenesis (such as ovariancancer, cervical cancer and prostate cancer), B cell lymphoma, T celllymphoma, cystic fibrosis, restenosis and Kawasaki disease.

The present invention provides for an isolated nucleic acid moleculeencoding a polypeptide wherein the encoded polypeptide comprises anamino acid sequence having at least 85%, at least 86%, at least 87%, atleast 88%, at least 89%, at least 90%, at least 91%, at least 92%, atleast 93%, at least 94%, at least 95%, at least 96%, at least 97%, atleast 98%, at least 99%, at least 99.5% sequence identity with aminoacid residues 200-458 of SEQ ID NO:158 (which includes exons8-16 ofIL-17RC), amino acid residues 33-458 of SEQ ID NO:158 (which includesexons 1-6 of IL-17A and 8-16 of IL-17RC), or amino acid residues 1-458of SEQ ID NO:158, or amino acid residues 33-690 of SEQ ID NO:158 oramino acid residues 1-690 of SEQ ID NO:158, wherein the polypeptidebinds IL-17A and/or IL-17F. The polypeptides may also be used to bind,block, reduce, antagonize or neutralize IL-17A and/or IL-17F and for usein the treatment of psoriasis, atopic and contact dermatitis, IBD, IBS,colitis, endotoxemia, arthritis, rheumatoid arthritis, Lyme diseasearthritis, psoriatic arthritis, adult respiratory disease (ARD), septicshock, multiple organ failure, inflammatory lung injury such as asthma,chronic obstructive pulmonary disease (COPD), airwayhyper-responsiveness, chronic bronchitis, allergic asthma, bacterialpneumonia, psoriasis, eczema, and inflammatory bowel disease such asulcerative colitis and Crohn's disease, helicobacter pylori infection,intraabdominal adhesions and/or abscesses as results of peritonealinflammation (i.e. from infection, injury, etc.), systemic lupuserythematosus (SLE), lupus nephritis, Diabetes Type I, coronary arterydisease, stroke, multiple sclerosis, systemic sclerosis, scleroderma,nephrotic syndrome, sepsis, organ allograft rejection, graft vs. hostdisease (GVHD), transplant rejection (e.g., kidney, lung, and heart),streptococcal cell wall (SCW)-induced arthritis, osteoarthritis,gingivitis/periodontitis, herpetic stromal keratitis, osteoporosis,neuritis, cancers including prostate, renal, colon, ovarian, cervical,leukemia, cancer angiogenesis (such as ovarian cancer, cervical cancerand prostate cancer), B cell lymphoma, T cell lymphoma, cystic fibrosis,restenosis and Kawasaki disease.

The present invention also provides an isolated nucleic acid moleculeencoding a polypeptide, wherein the nucleic acid molecule hybridizes tonucleotides 598-1374 of SEQ ID NO:157 (or full length complementthereof), nucleotides 97-1374 of SEQ ID NO:157 (or full lengthcomplement thereof), nucleotides 1-1374 of SEQ ID NO:157 (or full lengthcomplement thereof), nucleotides 97-2070 of SEQ ID NO:157 (or fulllength complement thereof) or nucleotides 1-2070 of SEQ ID NO:157 (orfull length complement thereof) under hybridization conditions ofprehybridization for 1 hour at 62° C. in hybridization solution (5×SSC(1×SSC is 0.15 M sodium chloride and 0.015 M sodium citrate), 0.02%sodium dodecyl sulfate (SDS), 0.1% N-lauroylsarcosine, 1% BlockingReagent) followed by two stringency washes with 2×SSC, 0.1% SDS for 5minutes at room temperature and once with 0.5×SSC, 0.1% SDS for 15minutes at 62° C., wherein the encoded polypeptide binds, blocks,reduces, antagonizes or neutralizes IL-17A and/or IL-17F. The encodedpolypeptide can also be used to treat psoriasis, atopic and contactdermatitis, IBD, IBS, colitis, endotoxemia, arthritis, rheumatoidarthritis, Lyme disease arthritis, psoriatic arthritis, adultrespiratory disease (ARD), septic shock, multiple organ failure,inflammatory lung injury such as asthma, chronic obstructive pulmonarydisease (COPD), airway hyper-responsiveness, chronic bronchitis,allergic asthma, bacterial pneumonia, psoriasis, eczema, andinflammatory bowel disease such as ulcerative colitis and Crohn'sdisease, helicobacter pylori infection, intraabdominal adhesions and/orabscesses as results of peritoneal inflammation (i.e. from infection,injury, etc.), systemic lupus erythematosus (SLE), lupus nephritis,Diabetes Type I, coronary artery disease, stroke, multiple sclerosis,systemic sclerosis, scleroderma, nephrotic syndrome, sepsis, organallograft rejection, graft vs. host disease (GVHD), transplant rejection(e.g., kidney, lung, and heart), streptococcal cell wall (SCW)-inducedarthritis, osteoarthritis, gingivitis/periodontitis, herpetic stromalkeratitis, osteoporosis, neuritis, cancers including prostate, renal,colon, ovarian, cervical, leukemia, cancer angiogenesis (such as ovariancancer, cervical cancer and prostate cancer), B cell lymphoma, T celllymphoma, cystic fibrosis, restenosis and Kawasaki disease.

In specific variations, the present invention provides an isolatedpolypeptide comprising amino acid residues 33-458 of SEQ ID NO:158(residues 1-426 of SEQ ID NO:183), amino acid residues 33-689 of SEQ IDNO:158 (residues 1-657 of SEQ ID NO:183), or amino acid residues 33-690of SEQ ID NO:158 (residues 1-658 of SEQ ID NO:183). Optionally, thepolypeptide may further comprise an immunogloblulin moiety, such as animmunoglobulin heavy chain constant region. The immunoglobulin heavychain constant region, for example, can be from IgG1, IgG2, IgG3, IgG4,IgA, IgD, IgM, IgE or a derivative thereof. The immunoglobulin heavychain constant region may be capable of mediating Antibody-DependentCell-mediated Cytotoxicity (“ADCC”) and/or Complement DependentCytotoxicity (“CDC”). The immunoglobulin heavy chain constant region canbe, for instance, Fc5, Fc10, amino acid residues 459-689 of SEQ IDNO:158 (residues 427-657 of SEQ ID NO:183) or amino acid residues459-690 of SEQ ID NO:158 (residues 427-658 of SEQ ID NO:183). Thepolypeptide may optionally further comprise a secretory signal sequence,such as, for example, the human IL-17RA signal sequence (e.g., SEQ IDNOs:184 and 185), human IL-17RC signal sequence (e.g., amino acidresidues 1-20 of SEQ ID NO:2), otPA pre-pro signal sequence (SEQ IDNO:178), human growth hormone signal sequence (SEQ ID NOs:168 and 169),or human CD33 signal sequence (SEQ ID NOs:172 and 173). The polypeptidecan be expressed recombinantly in cultured cells, such as prokaryoticcells (e.g., E. coli) and eukaryotic cells (e.g., mammalian cells suchas Chinese Hamster Ovary cells, and yeast cells such as Saccharomycescerevisiae and Pichia pastoris).

The present invention also provides isolated nucleic acid moleculesencoding a polypeptide comprising amino acid residues 33-458 of SEQ IDNO:158. The nucleic acid molecule can be, for instance, the nucleotidesequence shown as nucleotide residues 97-1374 of SEQ ID NO:157 (thenucleotide sequence of SEQ ID NO:182). Optionally, the encodedpolypeptide may further comprise an immunogloblulin moiety, such as animmunoglobulin heavy chain constant region. The immunoglobulin heavychain constant region, for example, can be from IgG1, IgG2, IgG3, IgG4,IgA, IgD, IgM, IgE or a derivative thereof. The immunoglobulin heavychain constant region may be capable of mediating Antibody-DependentCell-mediated Cytotoxicity (“ADCC”) and/or Complement DependentCytotoxicity (“CDC”). The immunoglobulin heavy chain constant region canbe, for instance, Fc5, Fc10, amino acid residues 459-689 of SEQ IDNO:158, or amino acid residues 459-690 of SEQ ID NO:158. The encodedpolypeptide may optionally further comprise a secretory signal sequence,such as, for example, the human IL-17RA signal sequence (e.g., SEQ IDNOs:184 and 185), human IL-17RC signal sequence (e.g., amino acidresidues 1-20 of SEQ ID NO:2), otPA pre-pro signal sequence (SEQ IDNO:178), human growth hormone signal sequence (SEQ ID NOs:168 and 169),or human CD33 signal sequence (SEQ ID NOs:172 and 173). The encodedpolypeptide can be expressed recombinantly in cultured cells, such asprokaryotic cells (e.g., E. coli) and eukaryotic cells (e.g., mammaliancells such as Chinese Hamster Ovary cells, and yeast cells such asSaccharomyces cerevisiae and Pichia pastoris).

The present invention also provides expression vectors comprising thefollowing operably linked elements: a) a transcription promoter; b) aDNA segement encoding a polypeptide wherein the encoded polypeptidecomprises amino acid residues 33-458 of SEQ ID NO:158; and c) atranscription terminator. The encoded polypeptide may further comprisean immunoglobulin moiety. The immunoglobulin heavy chain constantregion, for example, can be from IgG1, IgG2, IgG3, IgG4, IgA, IgD, IgM,IgE or a derivative thereof. The immunoglobulin heavy chain constantregion may be capable of mediating Antibody-Dependent Cell-mediatedCytotoxicity (“ADCC”) and/or Complement Dependent Cytotoxicity (“CDC”).The immunoglobulin heavy chain constant region can be, for instance,Fc5, Fc10, amino acid residues 459-689 of SEQ ID NO:158, or amino acidresidues 459-690 of SEQ ID NO:158. The encoded polypeptide mayoptionally further comprise a secretory signal sequence, such as, forexample, the human IL-17RA signal sequence (e.g., SEQ ID NOs:184 and185), human IL-17RC signal sequence (e.g., amino acid residues 1-20 ofSEQ ID NO:2), otPA pre-pro signal sequence (SEQ ID NO:178), human growthhormone signal sequence (SEQ ID NOs:168 and 169), and human CD33 signalsequence (SEQ ID NOs:172 and 173). The encoded polypeptide can beexpressed recombinantly in cultured cells, such as prokaryotic cells(e.g., E. coli) and eukaryotic cells (e.g., mammalian cells such asChinese Hamster Ovary cells, and yeast cells such as Saccharomycescerevisiae and Pichia pastoris). The present invention also provides amethod of producing a polypeptide comprising culturing a cell into whichhas been introduced an expression vector as described herein, whereinthe cell expresses the polypeptide encoded by the DNA segment, andrecovering the expressed polypeptide.

The present invention also provides for a composition comprising apolypeptide comprising amino acid residues 33-458 of SEQ ID NO:158 and apharmaceutically acceptable carrier. Optionally, the polypeptide mayfurther comprise an immunogloblulin moiety, such as an immunoglobulinheavy chain constant region. The immunoglobulin heavy chain constantregion, for example, can be from IgG1, IgG2, IgG3, IgG4, IgA, IgD, IgM,IgE or a derivative thereof. The immunoglobulin heavy chain constantregion may be capable of mediating Antibody-Dependent Cell-mediatedCytotoxicity (“ADCC”) and/or Complement Dependent Cytotoxicity (“CDC”).The immunoglobulin heavy chain constant region can be, for instance,Fc5, Fc10, amino acid residues 459-689 of SEQ ID NO:158, or amino acidresidues 459-690 of SEQ ID NO:158.

The present invention also provides for a method of treating a subjectsuffering from a disease comprising administering to the subject apolypeptide comprising amino acid residues 33-458 of SEQ ID NO:158,wherein the polypeptide binds, blocks, reduces, antagonizes orneutralizes IL-17A and/or IL-17F activity, and wherein the disease isselected from the group consisting of psoriasis, atopic and contactdermatitis, IBD, IBS, colitis, endotoxemia, arthritis, rheumatoidarthritis, Lyme disease arthritis, psoriatic arthritis, adultrespiratory disease (ARD), septic shock, multiple organ failure,inflammatory lung injury such as asthma, chronic obstructive pulmonarydisease (COPD), airway hyper-responsiveness, chronic bronchitis,allergic asthma, bacterial pneumonia, psoriasis, eczema, andinflammatory bowel disease such as ulcerative colitis and Crohn'sdisease, helicobacter pylori infection, intraabdominal adhesions and/orabscesses as results of peritoneal inflammation (i.e. from infection,injury, etc.), systemic lupus erythematosus (SLE), lupus nephritis,Diabetes Type I, coronary artery disease, stroke, multiple sclerosis,systemic sclerosis, scleroderma, nephrotic syndrome, sepsis, organallograft rejection, graft vs. host disease (GVHD), transplant rejection(e.g., kidney, lung, and heart), streptococcal cell wall (SCW)-inducedarthritis, osteoarthritis, gingivitis/periodontitis, herpetic stromalkeratitis, osteoporosis, neuritis, cancers including prostate, renal,colon, ovarian, cervical, leukemia, cancer angiogenesis (such as ovariancancer, cervical cancer and prostate cancer), B cell lymphoma, T celllymphoma, cystic fibrosis, restenosis and Kawasaki disease. Optionally,the polypeptide may further comprise an immunogloblulin moiety, such asan immunoglobulin heavy chain constant region. The immunoglobulin heavychain constant region, for example, can be from IgG1, IgG2, IgG3, IgG4,IgA, IgD, IgM, IgE or a derivative thereof. The immunoglobulin heavychain constant region may be capable of mediating Antibody-DependentCell-mediated Cytotoxicity (“ADCC”) and/or Complement DependentCytotoxicity (“CDC”). The immunoglobulin heavy chain constant region canbe, for instance, Fc5, Fc10, amino acid residues 459-689 of SEQ IDNO:158, or amino acid residues 459-690 of SEQ ID NO:158.

The present invention also provides for a method of treating a subjectsuffering from a disease comprising administering to the subject acomposition comprising a polypeptide comprising amino acid residues33-458 of SEQ ID NO:158, and a pharmaceutically acceptable carrierwherein the polypeptide binds, blocks, reduces, antagonizes orneutralizes IL-17A and/or IL-17F activity, and wherein the disease isselected from the group consisting of psoriasis, atopic and contactdermatitis, IBD, IBS, colitis, endotoxemia, arthritis, rheumatoidarthritis, Lyme disease arthritis, psoriatic arthritis, adultrespiratory disease (ARD), septic shock, multiple organ failure,inflammatory lung injury such as asthma, chronic obstructive pulmonarydisease (COPD), airway hyper-responsiveness, chronic bronchitis,allergic asthma, bacterial pneumonia, psoriasis, eczema, andinflammatory bowel disease such as ulcerative colitis and Crohn'sdisease, helicobacter pylori infection, intraabdominal adhesions and/orabscesses as results of peritoneal inflammation (i.e. from infection,injury, etc.), systemic lupus erythematosus (SLE), lupus nephritis,Diabetes Type I, coronary artery disease, stroke, multiple sclerosis,systemic sclerosis, scleroderma, nephrotic syndrome, sepsis, organallograft rejection, graft vs. host disease (GVHD), transplant rejection(e.g., kidney, lung, and heart), streptococcal cell wall (SCW)-inducedarthritis, osteoarthritis, gingivitis/periodontitis, herpetic stromalkeratitis, osteoporosis, neuritis, cancers including prostate, renal,colon, ovarian, cervical, leukemia, cancer angiogenesis (such as ovariancancer, cervical cancer and prostate cancer), B cell lymphoma, T celllymphoma, cystic fibrosis, restenosis and Kawasaki disease. Optionally,the polypeptide may further comprise an immunogloblulin moiety, such asan immunoglobulin heavy chain constant region. The immunoglobulin heavychain constant region, for example, can be from IgG1, IgG2, IgG3, IgG4,IgA, IgD, IgM, IgE or a derivative thereof. The immunoglobulin heavychain constant region may be capable of mediating Antibody-DependentCell-mediated Cytotoxicity (“ADCC”) and/or Complement DependentCytotoxicity (“CDC”). The immunoglobulin heavy chain constant region canbe, for instance, Fc5, Fc10, amino acid residues 458-689 of SEQ IDNO:158, or amino acid residues 458-690 of SEQ ID NO:158.

The present invention also provides an antibody or antibody fragmentthat specifically binds to a polypeptide comprising amino acid residues33-458 of SEQ ID NO:158, amino acid residues 33-689 of SEQ ID NO:158,and/or amino acid residues 33-690 of SEQ ID NO:158. The antibody can bean antibody selected from the group consisting of a polyclonal antibody,a murine monoclonal antibody, a humanized antibody derived from a murinemonoclonal antibody, an antibody fragment, neutralizing antibody, and ahuman monoclonal antibody. The antibody fragment may optionally be afragment selected from the group consisting of F(ab′)₂, F(ab)₂, Fab′,Fab, Fv, scFv, and minimal recognition unit. The present invention alsoprovides for an anti-idiotype antibody that specifically binds to anantibody or antibody fragment as described herein.

The present invention also provides fusion proteins comprising aminoacid residues 33-458 of SEQ ID NO:158 and an immunoglobulin moiety. Theimmunoglobulin moiety may optionally be an immunoglobulin heavy chainconstant region, such as amino acid residues 459-689 of SEQ ID NO:158 oramino acid residues 459-690 of SEQ ID NO:158. The present invention alsoprovides for an isolated nucleic acid molecule encoding a fusion proteinas described herein, such as nucleotides 97-2067 of SEQ ID NO:158(nucleotides 1-1971 of SEQ ID NO:182) or nucleotides 97-2070 of SEQ IDNO:158 (nucleotides 1-1974 of SEQ ID NO:182). The present invention alsoprovides compositions comprising the fusion proteins as described hereinand a pharmaceutically acceptable carrier. These compositions may beused to treat one or more of the various diseases as described herein.

Percent sequence identity is determined by conventional methods. See,e.g., Altschul et al., Bull. Math. Bio. 48:603 (1986), and Henikoff andHenikoff, Proc. Natl. Acad. Sci. USA 89:10915 (1992). Briefly, two aminoacid sequences are aligned to optimize the alignment scores using a gapopening penalty of 10, a gap extension penalty of 1, and the “BLOSUM62”scoring matrix of Henikoff and Henikoff (ibid.) as shown in Table 6(amino acids are indicated by the standard one-letter codes). Thepercent identity is then calculated as: ([Total number of identicalmatches]/[length of the longer sequence plus the number of gapsintroduced into the longer sequence in order to align the twosequences])(100).

TABLE 6 A R N D C Q E G H I L K M F P S T W Y V A 4 R −1 5 N −2 0 6 D −2−2 1 6 C 0 −3 −3 −3 9 Q −1 1 0 0 −3 5 E −1 0 0 2 −4 2 5 G 0 −2 0 −1 −3−2 −2 6 H −2 0 1 −1 −3 0 0 −2 8 I −1 −3 −3 −3 −1 −3 −3 −4 −3 4 L −1 −2−3 −4 −1 −2 −3 −4 −3 2 4 K −1 2 0 −1 −3 1 1 −2 −1 −3 −2 5 M −1 −1 −2 −3−1 0 −2 −3 −2 1 2 −1 5 F −2 −3 −3 −3 −2 −3 −3 −3 −1 0 0 −3 0 6 P −1 −2−2 −1 −3 −1 −1 −2 −2 −3 −3 −1 −2 −4 7 S 1 −1 1 0 −1 0 0 0 −1 −2 −2 0 −1−2 −1 4 T 0 −1 0 −1 −1 −1 −1 −2 −2 −1 −1 −1 −1 −2 −1 1 5 W −3 −3 −4 −4−2 −2 −3 −2 −2 −3 −2 −3 −1 1 −4 −3 −2 11 Y −2 −2 −2 −3 −2 −1 −2 −3 2 −1−1 −2 −1 3 −3 −2 −2 2 7 V 0 −3 −3 −3 −1 −2 −2 −3 −3 3 1 −2 1 −1 −2 −2 0−3 −1 4

Those skilled in the art appreciate that there are many establishedalgorithms available to align two amino acid sequences. The “FASTA”similarity search algorithm of Pearson and Lipman is a suitable proteinalignment method for examining the level of identity shared by an aminoacid sequence disclosed herein and the amino acid sequence of a putativeIL-17RC variant. The FASTA algorithm is described by Pearson and Lipman,Proc. Nat'l Acad. Sci. USA 85:2444 (1988), and by Pearson, Meth.Enzymol. 183:63 (1990). Briefly, FASTA first characterizes sequencesimilarity by identifying regions shared by the query sequence (e.g.,SEQ ID NO:2 or SEQ ID NO:3) and a test sequence that have either thehighest density of identities (if the ktup variable is 1) or pairs ofidentities (if ktup=2), without considering conservative amino acidsubstitutions, insertions, or deletions. The ten regions with thehighest density of identities are then rescored by comparing thesimilarity of all paired amino acids using an amino acid substitutionmatrix, and the ends of the regions are “trimmed” to include only thoseresidues that contribute to the highest score. If there are severalregions with scores greater than the “cutoff” value (calculated by apredetermined formula based upon the length of the sequence and the ktupvalue), then the trimmed initial regions are examined to determinewhether the regions can be joined to form an approximate alignment withgaps. Finally, the highest scoring regions of the two amino acidsequences are aligned using a modification of theNeedleman-Wunsch-Sellers algorithm (Needleman and Wunsch, J. Mol. Biol.48:444 (1970); Sellers, SIAM J. Appl. Math. 26:787 (1974)), which allowsfor amino acid insertions and deletions. Illustrative parameters forFASTA analysis are: ktup=1, gap opening penalty=10, gap extensionpenalty=1, and substitution matrix=BLOSUM62. These parameters can beintroduced into a FASTA program by modifying the scoring matrix file(“SMATRIX”), as explained in Appendix 2 of Pearson, Meth. Enzymol.183:63 (1990).

FASTA can also be used to determine the sequence identity of nucleicacid molecules using a ratio as disclosed above. For nucleotide sequencecomparisons, the ktup value can range between one to six, preferablyfrom three to six, most preferably three, with other parameters set asdescribed above.

The present invention includes nucleic acid molecules that encode apolypeptide having a conservative amino acid change, compared with anamino acid sequence disclosed herein. For example, variants can beobtained that contain one or more amino acid substitutions of SEQ IDNO:2 or 21, in which an alkyl amino acid is substituted for an alkylamino acid in a IL-17RA or IL-17RC amino acid sequence, an aromaticamino acid is substituted for an aromatic amino acid in a IL-17RA orIL-17RC amino acid sequence, a sulfur-containing amino acid issubstituted for a sulfur-containing amino acid in a IL-17RA or IL-17RCamino acid sequence, a hydroxy-containing amino acid is substituted fora hydroxy-containing amino acid in a IL-17RA or IL-17RC amino acidsequence, an acidic amino acid is substituted for an acidic amino acidin a IL-17RA or IL-17RC amino acid sequence, a basic amino acid issubstituted for a basic amino acid in a IL-17RA or IL-17RC amino acidsequence, or a dibasic monocarboxylic amino acid is substituted for adibasic monocarboxylic amino acid in a IL-17RA or IL-17RC amino acidsequence. Among the common amino acids, for example, a “conservativeamino acid substitution” is illustrated by a substitution among aminoacids within each of the following groups: (1) glycine, alanine, valine,leucine, and isoleucine, (2) phenylalanine, tyrosine, and tryptophan,(3) serine and threonine, (4) aspartate and glutamate, (5) glutamine andasparagine, and (6) lysine, arginine and histidine. The BLOSUM62 tableis an amino acid substitution matrix derived from about 2,000 localmultiple alignments of protein sequence segments, representing highlyconserved regions of more than 500 groups of related proteins (Henikoffand Henikoff, Proc. Nat'l Acad. Sci. USA 89:10915 (1992)). Accordingly,the BLOSUM62 substitution frequencies can be used to define conservativeamino acid substitutions that may be introduced into the amino acidsequences of the present invention. Although it is possible to designamino acid substitutions based solely upon chemical properties (asdiscussed above), the language “conservative amino acid substitution”preferably refers to a substitution represented by a BLOSUM62 value ofgreater than −1. For example, an amino acid substitution is conservativeif the substitution is characterized by a BLOSUM62 value of 0, 1, 2, or3. According to this system, preferred conservative amino acidsubstitutions are characterized by a BLOSUM62 value of at least 1 (e.g.,1, 2 or 3), while more preferred conservative amino acid substitutionsare characterized by a BLOSUM62 value of at least 2 (e.g., 2 or 3).Particular variants of IL-17RC are characterized by having at least 70%,at least 80%, at least 90%, at least 95% or greater than 95% such as96%, 97%, 98%, or 99% or greater sequence identity to the correspondingamino acid sequence (e.g., SEQ ID NO:2 or 21), wherein the variation inamino acid sequence is due to one or more conservative amino acidsubstitutions.

Conservative amino acid changes in a IL-17RA or IL-17RC gene can beintroduced, for example, by substituting nucleotides for the nucleotidesrecited in SEQ ID NO:1 or SEQ ID NO:4. Such “conservative amino acid”variants can be obtained by oligonucleotide-directed mutagenesis,linker-scanning mutagenesis, mutagenesis using the polymerase chainreaction, and the like (see Ausubel (1995); and McPherson (ed.),Directed Mutagenesis: A Practical Approach (IRL Press 1991)). A variantIL-17RC polypeptide can be identified by the ability to specificallybind anti-IL-17RC antibodies.

The proteins of the present invention can also comprise non-naturallyoccurring amino acid residues. Non-naturally occurring amino acidsinclude, without limitation, trans-3-methylproline, 2,4-methanoproline,cis-4-hydroxyproline, trans-4-hydroxyproline, N-methylglycine,allo-threonine, methylthreonine, hydroxyethylcysteine,hydroxyethylhomocysteine, nitroglutamine, homoglutamine, pipecolic acid,thiazolidine carboxylic acid, dehydroproline, 3- and 4-methylproline,3,3-dimethylproline, tert-leucine, norvaline, 2-azaphenylalanine,3-azaphenylalanine, 4-azaphenylalanine, and 4-fluorophenylalanine.Several methods are known in the art for incorporating non-naturallyoccurring amino acid residues into proteins. For example, an in vitrosystem can be employed wherein nonsense mutations are suppressed usingchemically aminoacylated suppressor tRNAs. Methods for synthesizingamino acids and aminoacylating tRNA are known in the art. Transcriptionand translation of plasmids containing nonsense mutations is typicallycarried out in a cell-free system comprising an E. coli S30 extract andcommercially available enzymes and other reagents. Proteins are purifiedby chromatography. See, for example, Robertson et al., J. Am. Chem. Soc.113:2722 (1991), Ellman et al., Methods Enzymol. 202:301 (1991), Chunget al., Science 259:806 (1993), and Chung et al., Proc. Nat'l Acad. Sci.USA 90:10145 (1993).

In a second method, translation is carried out in Xenopus oocytes bymicroinjection of mutated mRNA and chemically aminoacylated suppressortRNAs (Turcatti et al., J. Biol. Chem. 271:19991 (1996)). Within a thirdmethod, E. coli cells are cultured in the absence of a natural aminoacid that is to be replaced (e.g., phenylalanine) and in the presence ofthe desired non-naturally occurring amino acid(s) (e.g.,2-azaphenylalanine, 3-azaphenylalanine, 4-azaphenylalanine, or4-fluorophenylalanine). The non-naturally occurring amino acid isincorporated into the protein in place of its natural counterpart. See,Koide et al., Biochem. 33:7470 (1994). Naturally occurring amino acidresidues can be converted to non-naturally occurring species by in vitrochemical modification. Chemical modification can be combined withsite-directed mutagenesis to further expand the range of substitutions(Wynn and Richards, Protein Sci. 2:395 (1993)).

A limited number of non-conservative amino acids, amino acids that arenot encoded by the genetic code, non-naturally occurring amino acids,and unnatural amino acids may be substituted for IL-17RA or IL-17RCamino acid residues.

Essential amino acids in the polypeptides of the present invention canbe identified according to procedures known in the art, such assite-directed mutagenesis or alanine-scanning mutagenesis (Cunninghamand Wells, Science 244:1081 (1989), Bass et al., Proc. Nat'l Acad. Sci.USA 88:4498 (1991), Coombs and Corey, “Site-Directed Mutagenesis andProtein Engineering,” in Proteins: Analysis and Design, Angeletti (ed.),pages 259-311 (Academic Press, Inc. 1998)). In the latter technique,single alanine mutations are introduced at every residue in themolecule, and the resultant mutant molecules are tested for biologicalactivity to identify amino acid residues that are critical to theactivity of the molecule. See also, Hilton et al., J. Biol. Chem.271:4699 (1996).

Although sequence analysis can be used to further define the IL-17RA orIL-17RC ligand binding region, amino acids that play a role in IL-17RAor IL-17RC binding activity (such as binding of IL-17RC to either Il-17Aor IL-17F, and IL-17RA to IL-17A) can also be determined by physicalanalysis of structure, as determined by such techniques as nuclearmagnetic resonance, crystallography, electron diffraction orphotoaffinity labeling, in conjunction with mutation of putative contactsite amino acids. See, e.g., de Vos et al., Science 255:306 (1992),Smith et al., J. Mol. Biol. 224:899 (1992), and Wlodaver et al., FEBSLett. 309:59 (1992). Specifically, three domains were identified:

1) Domain 1 (SEQ ID NOs: 159 and 160) comprises exons 8-10 of IL-17RC.This corresponds to IL-17RCx1's amino acid residues 193-276 of (SEQ IDNO:2) and IL-17RCx4's amino acid residues 208-291 of (SEQ ID NO:166).

2) Domain 2 (SEQ ID NOs: 161 and 162) comprises exons 11-13 of IL-17RC.This corresponds to IL-17RCx1's amino acid residues 277-370 of (SEQ IDNO:2) and IL-17RCx4's amino acid residues 292-385 of (SEQ ID NO:166).

3) Domain 3 (SEQ ID NOs: 163 and 164) comprises exons 14-16 of IL-17RC.This corresponds to IL-17RCx1's amino acid residues 371-447 of (SEQ IDNO:2) and IL-17RCx4's amino acid residues 386-462 of (SEQ ID NO:166).

Multiple amino acid substitutions can be made and tested using knownmethods of mutagenesis and screening, such as those disclosed byReidhaar-Olson and Sauer (Science 241:53 (1988)) or Bowie and Sauer(Proc. Nat'l Acad. Sci. USA 86:2152 (1989)). Briefly, these authorsdisclose methods for simultaneously randomizing two or more positions ina polypeptide, selecting for functional polypeptide, and then sequencingthe mutagenized polypeptides to determine the spectrum of allowablesubstitutions at each position. Other methods that can be used includephage display (e.g., Lowman et al., Biochem. 30:10832 (1991), Ladner etal., U.S. Pat. No. 5,223,409, Huse, international publication No. WO92/06204, and region-directed mutagenesis (Derbyshire et al., Gene46:145 (1986), and Ner et al., DNA 7:127, (1988)). Moreover, IL-17RC orIL-17RA labeled with biotin or FITC can be used for expression cloningof IL-17RC ligands.

Variants of the disclosed IL-17RC or IL-17RA nucleotide and polypeptidesequences can also be generated through DNA shuffling as disclosed byStemmer, Nature 370:389 (1994), Stemmer, Proc. Nat'l Acad. Sci. USA91:10747 (1994), and international publication No. WO 97/20078. Briefly,variant DNA molecules are generated by in vitro homologous recombinationby random fragmentation of a parent DNA followed by reassembly usingPCR, resulting in randomly introduced point mutations. This techniquecan be modified by using a family of parent DNA molecules, such asallelic variants or DNA molecules from different species, to introduceadditional variability into the process. Selection or screening for thedesired activity, followed by additional iterations of mutagenesis andassay provides for rapid “evolution” of sequences by selecting fordesirable mutations while simultaneously selecting against detrimentalchanges.

Mutagenesis methods as disclosed herein can be combined withhigh-throughput, automated screening methods to detect activity ofcloned, mutagenized polypeptides in host cells. Mutagenized DNAmolecules that encode biologically active polypeptides, or polypeptidesthat bind with anti-IL-17RC or IL-17RA antibodies, can be recovered fromthe host cells and rapidly sequenced using modern equipment. Thesemethods allow the rapid determination of the importance of individualamino acid residues in a polypeptide of interest, and can be applied topolypeptides of unknown structure.

The present invention also includes “functional fragments” of IL-17RC orIL-17RA polypeptides and nucleic acid molecules encoding such functionalfragments. These functional fragments may either bind ligand or ligands(i.e. both IL-17A and IL-17F) singly or together. Routine deletionanalyses of nucleic acid molecules can be performed to obtain functionalfragments of a nucleic acid molecule that encodes a IL-17RC or IL-17RApolypeptide. As an illustration, DNA molecules having the nucleotidesequence of SEQ ID NO:1 or SEQ ID NO:4 can be digested with Bal31nuclease to obtain a series of nested deletions. The fragments are theninserted into expression vectors in proper reading frame, and theexpressed polypeptides are isolated and tested for the ability to bindanti-IL-17RC antibodies. One alternative to exonuclease digestion is touse oligonucleotide-directed mutagenesis to introduce deletions or stopcodons to specify production of a desired fragment. Alternatively,particular fragments of a IL-17RC or IL-17RA gene can be synthesizedusing the polymerase chain reaction.

This general approach is exemplified by studies on the truncation ateither or both termini of interferons have been summarized byHorisberger and Di Marco, Pharmac. Ther. 66:507 (1995). Moreover,standard techniques for functional analysis of proteins are describedby, for example, Treuter et al., Molec. Gen. Genet. 240:113 (1993),Content et al., “Expression and preliminary deletion analysis of the 42kDa 2-5A synthetase induced by human interferon,” in BiologicalInterferon Systems, Proceedings of ISIR-TNO Meeting on InterferonSystems, Cantell (ed.), pages 65-72 (Nijhoff 1987), Herschman, “The EGFReceptor,” in Control of Animal Cell Proliferation, Vol. 1, Boynton etal., (eds.) pages 169-199 (Academic Press 1985), Coumailleau et al., J.Biol. Chem. 270:29270 (1995); Fukunaga et al., J. Biol. Chem. 270:25291(1995); Yamaguchi et al., Biochem. Pharmacol. 50:1295 (1995), and Meiselet al., Plant Molec. Biol. 30:1 (1996).

The present invention also contemplates functional fragments of aIL-17RC or IL-17RA gene that have amino acid changes, compared with anamino acid sequence disclosed herein. A variant IL-17RC or IL-17RA genecan be identified on the basis of structure by determining the level ofidentity with disclosed nucleotide and amino acid sequences, asdiscussed above. An alternative approach to identifying a variant geneon the basis of structure is to determine whether a nucleic acidmolecule encoding a potential variant IL-17RC or IL-17RA gene canhybridize to a nucleic acid molecule comprising a nucleotide sequence,such as SEQ ID NO:1 or SEQ ID NO:4.

The present invention also includes using functional fragments ofIL-17RC or IL-17RA polypeptides, antigenic epitopes, epitope-bearingportions or ligand-binding portions of IL-17RC and/or IL-17RApolypeptides, and nucleic acid molecules that encode such functionalfragments, antigenic epitopes, epitope-bearing portions orligand-binding portions of IL-17RC and/or IL-17RA polypeptides. Suchfragments are used to generate polypeptides for use in generatingsoluble receptors or binding molecules that bind, block, inhibit,reduce, antagonize or neutralize activity of IL-17A or IL-17F or bothIL-17A and IL-17F. A “functional” IL-17RC or IL-17RC/IL-17RA polypeptideor fragment thereof as defined herein is characterized by its ability toblock, inhibit, reduce, antagonize or neutralize IL-17A and/or IL-17Finflammatory, proliferative or differentiating activity, by its abilityto induce or inhibit specialized cell functions, or by its ability tobind specifically to IL-17A and/or IL-17F. As previously describedherein, both IL-17RA and IL-17RC is characterized by a unique cytokinereceptor structure and domains as described herein. Thus, the presentinvention further contemplates using fusion proteins encompassing: (a)polypeptide molecules comprising one or more of the domains describedabove; and (b) functional fragments comprising one or more of thesedomains. The other polypeptide portion of the fusion protein may becontributed by another cytokine receptor, such as an IL-17-likereceptor, IL-17RA, IL-17RE, IL-17RD, or by a non-native and/or anunrelated secretory signal peptide that facilitates secretion of thefusion protein.

The present invention also provides polypeptide fragments or peptidescomprising an ligand-binding portion of a IL-17RC or IL-17RA polypeptidedescribed herein. Such fragments or peptides may comprise a portion ofeither IL-17RC or IL-17RA that binds to its respective ligand (IL-17Aand/or IL-17F).

For any IL-17RC or IL-17RA polypeptide, including variants and fusionproteins, one of ordinary skill in the art can readily generate a fullydegenerate polynucleotide sequence encoding that variant using theinformation set forth in Tables 1 and 2 above. Moreover, those of skillin the art can use standard software to devise IL-17RC or IL-17RAvariants based upon the nucleotide and amino acid sequences describedherein.

E) Production of IL-17RC, IL-17RA and IL-17RC/IL-17RA Polypeptides

The polypeptides of the present invention, including full-lengthpolypeptides; soluble monomeric, homodimeric, heterodimeric andmultimeric receptors; full-length receptors; receptor fragments (e.g.ligand-binding fragments and antigenic epitopes), functional fragments,and fusion proteins, can be produced in recombinant host cells followingconventional techniques. To express an IL-17RC, IL-17RA andIL-17RC/IL-17RA gene, a nucleic acid molecule encoding the polypeptidemust be operably linked to regulatory sequences that controltranscriptional expression in an expression vector and then, introducedinto a host cell. In addition to transcriptional regulatory sequences,such as promoters and enhancers, expression vectors can includetranslational regulatory sequences and a marker gene which is suitablefor selection of cells that carry the expression vector.

Expression vectors that are suitable for production of a foreign proteinin eukaryotic cells typically contain (1) prokaryotic DNA elementscoding for a bacterial replication origin and an antibiotic resistancemarker to provide for the growth and selection of the expression vectorin a bacterial host; (2) eukaryotic DNA elements that control initiationof transcription, such as a promoter; and (3) DNA elements that controlthe processing of transcripts, such as a transcriptiontermination/polyadenylation sequence. As discussed above, expressionvectors can also include nucleotide sequences encoding a secretorysequence that directs the heterologous polypeptide into the secretorypathway of a host cell. For example, an IL-17RC expression vector maycomprise an IL-17RC, IL-17RA and IL-17RC/IL-17RA gene and a secretorysequence derived from any secreted gene.

IL-17RC, IL-17RA and IL-17RC/IL-17RA proteins of the present inventionmay be expressed in mammalian cells. Examples of suitable mammalian hostcells include African green monkey kidney cells (Vero; ATCC CRL 1587),human embryonic kidney cells (293-HEK; ATCC CRL 1573), baby hamsterkidney cells (BHK-21, BHK-570; ATCC CRL 8544, ATCC CRL 10314), caninekidney cells (MDCK; ATCC CCL 34), Chinese hamster ovary cells (CHO-K1;ATCC CCL61; CHO DG44 (Chasin et al., Som. Cell. Molec. Genet. 12:555,1986)), rat pituitary cells (GH1; ATCC CCL82), HeLa S3 cells (ATCCCCL2.2), rat hepatoma cells (H-4-II-E; ATCC CRL 1548) SV40-transformedmonkey kidney cells (COS-1; ATCC CRL 1650) and murine embryonic cells(NIH-3T3; ATCC CRL 1658).

For a mammalian host, the transcriptional and translational regulatorysignals may be derived from mammalian viral sources, for example,adenovirus, bovine papilloma virus, simian virus, or the like, in whichthe regulatory signals are associated with a particular gene which has ahigh level of expression. Suitable transcriptional and translationalregulatory sequences also can be obtained from mammalian genes, forexample, actin, collagen, myosin, and metallothionein genes.

Transcriptional regulatory sequences include a promoter regionsufficient to direct the initiation of RNA synthesis. Suitableeukaryotic promoters include the promoter of the mouse metallothionein Igene (Hamer et al., J. Molec. Appl. Genet. 1:273 (1982)), the TKpromoter of Herpes virus (McKnight, Cell 31:355 (1982)), the SV40 earlypromoter (Benoist et al., Nature 290:304 (1981)), the Rous sarcoma viruspromoter (Gorman et al., Proc. Nat'l Acad. Sci. USA 79:6777 (1982)), thecytomegalovirus promoter (Foecking et al., Gene 45:101 (1980)), and themouse mammary tumor virus promoter (see, generally, Etcheverry,“Expression of Engineered Proteins in Mammalian Cell Culture,” inProtein Engineering: Principles and Practice, Cleland et al. (eds.),pages 163-181 (John Wiley & Sons, Inc. 1996)).

Alternatively, a prokaryotic promoter, such as the bacteriophage T3 RNApolymerase promoter, can be used to control gene expression in mammaliancells if the prokaryotic promoter is regulated by a eukaryotic promoter(Zhou et al., Mol. Cell. Biol. 10:4529 (1990), and Kaufman et al., Nucl.Acids Res. 19:4485 (1991)).

In certain embodiments, a DNA sequence encoding an IL-17RC, IL-17RA andIL-17RC/IL-17RA soluble receptor polypeptide, or a fragment of IL-17RC,IL-17RA or IL-17RC/IL-17RA polypeptide is operably linked to othergenetic elements required for its expression, generally including atranscription promoter and terminator, within an expression vector. Thevector will also commonly contain one or more selectable markers and oneor more origins of replication, although those skilled in the art willrecognize that within certain systems selectable markers may be providedon separate vectors, and replication of the exogenous DNA may beprovided by integration into the host cell genome. Selection ofpromoters, terminators, selectable markers, vectors and other elementsis a matter of routine design within the level of ordinary skill in theart. Many such elements are described in the literature and areavailable through commercial suppliers. Multiple components of a solublereceptor complex can be co-transfected on individual expression vectorsor be contained in a single expression vector. Such techniques ofexpressing multiple components of protein complexes are well known inthe art.

An expression vector can be introduced into host cells using a varietyof standard techniques including calcium phosphate transfection,liposome-mediated transfection, microprojectile-mediated delivery,electroporation, and the like. The transfected cells can be selected andpropagated to provide recombinant host cells that comprise theexpression vector stably integrated in the host cell genome. Techniquesfor introducing vectors into eukaryotic cells and techniques forselecting such stable transformants using a dominant selectable markerare described, for example, by Ausubel (1995) and by Murray (ed.), GeneTransfer and Expression Protocols (Humana Press 1991).

For example, one suitable selectable marker is a gene that providesresistance to the antibiotic neomycin. In this case, selection iscarried out in the presence of a neomycin-type drug, such as G-418 orthe like. Selection systems can also be used to increase the expressionlevel of the gene of interest, a process referred to as “amplification.”Amplification is carried out by culturing transfectants in the presenceof a low level of the selective agent and then increasing the amount ofselective agent to select for cells that produce high levels of theproducts of the introduced genes. A suitable amplifiable selectablemarker is dihydrofolate reductase (DHFR), which confers resistance tomethotrexate. Other drug resistance genes (e.g., hygromycin resistance,multi-drug resistance, puromycin acetyltransferase) can also be used.Alternatively, markers that introduce an altered phenotype, such asgreen fluorescent protein, or cell surface proteins such as CD4, CD8,Class I MHC, placental alkaline phosphatase may be used to sorttransfected cells from untransfected cells by such means as FACS sortingor magnetic bead separation technology.

The polypeptides of the invention can also be produced by culturedmammalian cells using a viral delivery system. Exemplary viruses forthis purpose include adenovirus, retroviruses, herpesvirus, vacciniavirus and adeno-associated virus (AAV). Adenovirus, a double-strandedDNA virus, is currently the best studied gene transfer vector fordelivery of heterologous nucleic acid (for a review, see Becker et al.,Meth. Cell Biol. 43:161 (1994), and Douglas and Curiel, Science &Medicine 4:44 (1997)). Advantages of the adenovirus system include theaccommodation of relatively large DNA inserts, the ability to grow tohigh-titer, the ability to infect a broad range of mammalian cell types,and flexibility that allows use with a large number of available vectorscontaining different promoters.

By deleting portions of the adenovirus genome, larger inserts (up to 7kb) of heterologous DNA can be accommodated. These inserts can beincorporated into the viral DNA by direct ligation or by homologousrecombination with a co-transfected plasmid. An option is to delete theessential E1 gene from the viral vector, which results in the inabilityto replicate unless the E1 gene is provided by the host cell. Adenovirusvector-infected human 293 cells (ATCC Nos. CRL-1573, 45504, 45505), forexample, can be grown as adherent cells or in suspension culture atrelatively high cell density to produce significant amounts of protein(see Garnier et al., Cytotechnol. 15:145 (1994)).

The polypeptides of the invention can also be expressed in other highereukaryotic cells, such as avian, fungal, insect, yeast, or plant cells.The baculovirus system provides an efficient means to introduce clonedgenes into insect cells. Suitable expression vectors are based upon theAutographa californica multiple nuclear polyhedrosis virus (AcMNPV), andcontain well-known promoters such as Drosophila heat shock protein (hsp)70 promoter, Autographa californica nuclear polyhedrosis virusimmediate-early gene promoter (ie-1) and the delayed early 39K promoter,baculovirus p10 promoter, and the Drosophila metallothionein promoter. Asecond method of making recombinant baculovirus utilizes atransposon-based system described by Luckow (Luckow, et al., J. Virol.67:4566 (1993)). This system, which utilizes transfer vectors, is soldin the BAC-to-BAC kit (Life Technologies, Rockville, Md.). This systemutilizes a transfer vector, PFASTBAC (Life Technologies) containing aTn7 transposon to move the DNA encoding a polypeptide into a baculovirusgenome maintained in E. coli as a large plasmid called a “bacmid.” See,Hill-Perkins and Possee, J. Gen. Virol. 71:971 (1990), Bonning, et al.,J. Gen. Virol. 75:1551 (1994), and Chazenbalk, and Rapoport, J. Biol.Chem. 270:1543 (1995). In addition, transfer vectors can include anin-frame fusion with DNA encoding an epitope tag at the C- or N-terminusof the expressed the polypeptide, for example, a Glu-Glu epitope tag(Grussenmeyer et al., Proc. Nat'l Acad. Sci. 82:7952 (1985)). Using atechnique known in the art, a transfer vector containing a gene encodinga polypeptide of the present invention is transformed into E. coli, andscreened for bacmids which contain an interrupted lacZ gene indicativeof recombinant baculovirus. The bacmid DNA containing the recombinantbaculovirus genome is then isolated using common techniques.

The illustrative PFASTBAC vector can be modified to a considerabledegree. For example, the polyhedrin promoter can be removed andsubstituted with the baculovirus basic protein promoter (also known asPcor, p6.9 or MP promoter) which is expressed earlier in the baculovirusinfection, and has been shown to be advantageous for expressing secretedproteins (see, for example, Hill-Perkins and Possee, J. Gen. Virol.71:971 (1990), Bonning, et al., J. Gen. Virol. 75:1551 (1994), andChazenbalk and Rapoport, J. Biol. Chem. 270:1543 (1995). In suchtransfer vector constructs, a short or long version of the basic proteinpromoter can be used. Moreover, transfer vectors can be constructedwhich replace the native secretory signal sequences with secretorysignal sequences derived from insect proteins. For example, a secretorysignal sequence from Ecdysteroid Glucosyltransferase (EGT), honey beeMelittin (Invitrogen Corporation; Carlsbad, Calif.), or baculovirus gp67(PharMingen: San Diego, Calif.) can be used in constructs to replace thenative IL-17RC secretory signal sequence.

The recombinant virus or bacmid is used to transfect host cells.Suitable insect host cells include cell lines derived from IPLB-Sf-21, aSpodoptera frugiperda pupal ovarian cell line, such as Sf9 (ATCC CRL1711), Sf21AE, and Sf21 (Invitrogen Corporation; San Diego, Calif.), aswell as Drosophila Schneider-2 cells, and the HIGH FIVEO cell line(Invitrogen) derived from Trichoplusia ni (U.S. Pat. No. 5,300,435).Commercially available serum-free media can be used to grow and tomaintain the cells. Suitable media are Sf900 II™ (Life Technologies) orESF 921™ (Expression Systems) for the Sf9 cells; and Ex-CellO10405™ (JRHBiosciences, Lenexa, Kans.) or Express FiveO™ (Life Technologies) forthe T. ni cells. When recombinant virus is used, the cells are typicallygrown up from an inoculation density of approximately 2-5×10⁵ cells to adensity of 1-2×10⁶ cells at which time a recombinant viral stock isadded at a multiplicity of infection (MOI) of 0.1 to 10, more typicallynear 3.

Established techniques for producing recombinant proteins in baculovirussystems are provided by Bailey et al., “Manipulation of BaculovirusVectors,” in Methods in Molecular Biology, Volume 7: Gene Transfer andExpression Protocols, Murray (ed.), pages 147-168 (The Humana Press,Inc. 1991), by Patel et al., “The baculovirus expression system,” in DNACloning 2: Expression Systems, 2nd Edition, Glover et al. (eds.), pages205-244 (Oxford University Press 1995), by Ausubel (1995) at pages 16-37to 16-57, by Richardson (ed.), Baculovirus Expression Protocols (TheHumana Press, Inc. 1995), and by Lucknow, “Insect Cell ExpressionTechnology,” in Protein Engineering: Principles and Practice, Cleland etal. (eds.), pages 183-218 (John Wiley & Sons, Inc. 1996).

Fungal cells, including yeast cells, can also be used to express thegenes described herein. Yeast species of particular interest in thisregard include Saccharomyces cerevisiae, Pichia pastoris, and Pichiamethanolica. Suitable promoters for expression in yeast includepromoters from GAL1 (galactose), PGK (phosphoglycerate kinase), ADH(alcohol dehydrogenase), AOX1 (alcohol oxidase), HIS4 (histidinoldehydrogenase), and the like. Many yeast cloning vectors have beendesigned and are readily available. These vectors include YIp-basedvectors, such as YIp5, YRp vectors, such as YRp17, YEp vectors such asYEp13 and YCp vectors, such as YCp19. Methods for transforming S.cerevisiae cells with exogenous DNA and producing recombinantpolypeptides therefrom are disclosed by, for example, Kawasaki, U.S.Pat. No. 4,599,311, Kawasaki et al., U.S. Pat. No. 4,931,373, Brake,U.S. Pat. No. 4,870,008, Welch et al., U.S. Pat. No. 5,037,743, andMurray et al., U.S. Pat. No. 4,845,075. Transformed cells are selectedby phenotype determined by the selectable marker, commonly drugresistance or the ability to grow in the absence of a particularnutrient (e.g., leucine). A suitable vector system for use inSaccharomyces cerevisiae is the POT1 vector system disclosed by Kawasakiet al. (U.S. Pat. No. 4,931,373), which allows transformed cells to beselected by growth in glucose-containing media. Additional suitablepromoters and terminators for use in yeast include those from glycolyticenzyme genes (see, e.g., Kawasaki, U.S. Pat. No. 4,599,311, Kingsman etal., U.S. Pat. No. 4,615,974, and Bitter, U.S. Pat. No. 4,977,092) andalcohol dehydrogenase genes. See also U.S. Pat. Nos. 4,990,446,5,063,154, 5,139,936, and 4,661,454.

Transformation systems for other yeasts, including Hansenula polymorpha,Schizosaccharomyces pombe, Kluyveromyces lactis, Kluyveromyces fragilis,Ustilago maydis, Pichia pastoris, Pichia methanolica, Pichiaguillermondii and Candida maltosa are known in the art. See, forexample, Gleeson et al., J. Gen. Microbiol. 132:3459 (1986), and Cregg,U.S. Pat. No. 4,882,279. Aspergillus cells may be utilized according tothe methods of McKnight et al., U.S. Pat. No. 4,935,349. Methods fortransforming Acremonium chrysogenum are disclosed by Sumino et al., U.S.Pat. No. 5,162,228. Methods for transforming Neurospora are disclosed byLambowitz, U.S. Pat. No. 4,486,533.

For example, the use of Pichia methanolica as host for the production ofrecombinant proteins is disclosed by Raymond, U.S. Pat. No. 5,716,808,Raymond, U.S. Pat. No. 5,736,383, Raymond et al., Yeast 14:11-23 (1998),and in international publication Nos. WO 97/17450, WO 97/17451, WO98/02536, and WO 98/02565. DNA molecules for use in transforming P.methanolica will commonly be prepared as double-stranded, circularplasmids, which are preferably linearized prior to transformation. Forpolypeptide production in P. methanolica, the promoter and terminator inthe plasmid can be that of a P. methanolica gene, such as a P.methanolica alcohol utilization gene (AUG1 or AUG2). Other usefulpromoters include those of the dihydroxyacetone synthase (DHAS), formatedehydrogenase (FMD), and catalase (CAT) genes. To facilitate integrationof the DNA into the host chromosome, it is preferred to have the entireexpression segment of the plasmid flanked at both ends by host DNAsequences. A suitable selectable marker for use in Pichia methanolica isa P. methanolica ADE2 gene, which encodesphosphoribosyl-5-aminoimidazole carboxylase (AIRC; EC 4.1.1.21), andwhich allows ade2 host cells to grow in the absence of adenine. Forlarge-scale, industrial processes where it is desirable to minimize theuse of methanol, host cells can be used in which both methanolutilization genes (AUG1 and AUG2) are deleted. For production ofsecreted proteins, host cells can be deficient in vacuolar proteasegenes (PEP4 and PRB1). Electroporation is used to facilitate theintroduction of a plasmid containing DNA encoding a polypeptide ofinterest into P. methanolica cells. P. methanolica cells can betransformed by electroporation using an exponentially decaying, pulsedelectric field having a field strength of from 2.5 to 4.5 kV/cm,preferably about 3.75 kV/cm, and a time constant (t) of from 1 to 40milliseconds, most preferably about 20 milliseconds.

Expression vectors can also be introduced into plant protoplasts, intactplant tissues, or isolated plant cells. Methods for introducingexpression vectors into plant tissue include the direct infection orco-cultivation of plant tissue with Agrobacterium tumefaciens,microprojectile-mediated delivery, DNA injection, electroporation, andthe like. See, for example, Horsch et al., Science 227:1229 (1985),Klein et al., Biotechnology 10:268 (1992), and Mild et al., “Proceduresfor Introducing Foreign DNA into Plants,” in Methods in Plant MolecularBiology and Biotechnology, Glick et al. (eds.), pages 67-88 (CRC Press,1993).

Alternatively, genes encoding the polypeptides of the present inventioncan be expressed in prokaryotic host cells. Suitable promoters that canbe used to express IL-17RC polypeptides in a prokaryotic host arewell-known to those of skill in the art and include promoters capable ofrecognizing the T4, T3, Sp6 and T7 polymerases, the P_(R) and P_(L)promoters of bacteriophage lambda, the trp, recA, heat shock, lacUV5,tac, lpp-lacSpr, phoA, and lacZ promoters of E. coli, promoters of B.subtilis, the promoters of the bacteriophages of Bacillus, Streptomycespromoters, the int promoter of bacteriophage lambda, the bla promoter ofpBR322, and the CAT promoter of the chloramphenicol acetyl transferasegene. Prokaryotic promoters have been reviewed by Glick, J. Ind.Microbiol. 1:277 (1987), Watson et al., Molecular Biology of the Gene,4th Ed. (Benjamin Cummins 1987), and by Ausubel et al. (1995).

Suitable prokaryotic hosts include E. coli and Bacillus subtilus.Suitable strains of E. coli include BL21(DE3), BL21(DE3)pLysS,BL21(DE3)pLysE, DH1, DH4I, DH5, DHSI, DHSIF′, DHSIMCR, DH10B, DH10B/p3,DH11S, C600, HB101, JM101, JM105, JM109, JM110, K38, RR1, Y1088, Y1089,CSH18, ER1451, and ER1647 (see, for example, Brown (ed.), MolecularBiology Labfax (Academic Press 1991)). Suitable strains of Bacillussubtilus include BR151, YB886, MI119, MI120, and B170 (see, for example,Hardy, “Bacillus Cloning Methods,” in DNA Cloning: A Practical Approach,Glover (ed.) (IRL Press 1985)).

When expressing a polypeptide of the present invention in bacteria suchas E. coli, the polypeptide may be retained in the cytoplasm, typicallyas insoluble granules, or may be directed to the periplasmic space by abacterial secretion sequence. In the former case, the cells are lysed,and the granules are recovered and denatured using, for example,guanidine isothiocyanate or urea. The denatured polypeptide can then berefolded and dimerized by diluting the denaturant, such as by dialysisagainst a solution of urea and a combination of reduced and oxidizedglutathione, followed by dialysis against a buffered saline solution. Inthe latter case, the polypeptide can be recovered from the periplasmicspace in a soluble and functional form by disrupting the cells (by, forexample, sonication or osmotic shock) to release the contents of theperiplasmic space and recovering the protein, thereby obviating the needfor denaturation and refolding.

Methods for expressing proteins in prokaryotic hosts are well-known tothose of skill in the art (see, for example, Williams et al.,“Expression of foreign proteins in E. coli using plasmid vectors andpurification of specific polyclonal antibodies,” in DNA Cloning 2:Expression Systems, 2nd Edition, Glover et al. (eds.), page 15 (OxfordUniversity Press 1995), Ward et al., “Genetic Manipulation andExpression of Antibodies,” in Monoclonal Antibodies: Principles andApplications, page 137 (Wiley-Liss, Inc. 1995), and Georgiou,“Expression of Proteins in Bacteria,” in Protein Engineering: Principlesand Practice, Cleland et al. (eds.), page 101 (John Wiley & Sons, Inc.1996)).

Standard methods for introducing expression vectors into bacterial,yeast, insect, and plant cells are provided, for example, by Ausubel(1995).

General methods for expressing and recovering foreign protein producedby a mammalian cell system are provided by, for example, Etcheverry,“Expression of Engineered Proteins in Mammalian Cell Culture,” inProtein Engineering: Principles and Practice, Cleland et al. (eds.),pages 163 (Wiley-Liss, Inc. 1996). Standard techniques for recoveringprotein produced by a bacterial system is provided by, for example,Grisshammer et al., “Purification of over-produced proteins from E. colicells,” in DNA Cloning 2: Expression Systems, 2nd Edition, Glover et al.(eds.), pages 59-92 (Oxford University Press 1995). Established methodsfor isolating recombinant proteins from a baculovirus system aredescribed by Richardson (ed.), Baculovirus Expression Protocols (TheHumana Press, Inc. 1995).

As an alternative, polypeptides of the present invention can besynthesized by exclusive solid phase synthesis, partial solid phasemethods, fragment condensation or classical solution synthesis. Thesesynthesis methods are well-known to those of skill in the art (see, forexample, Merrifield, J. Am. Chem. Soc. 85:2149 (1963), Stewart et al.,“Solid Phase Peptide Synthesis” (2nd Edition), (Pierce Chemical Co.1984), Bayer and Rapp, Chem. Pept. Prot. 3:3 (1986), Atherton et al.,Solid Phase Peptide Synthesis: A Practical Approach (IRL Press 1989),Fields and Colowick, “Solid-Phase Peptide Synthesis,” Methods inEnzymology Volume 289 (Academic Press 1997), and Lloyd-Williams et al.,Chemical Approaches to the Synthesis of Peptides and Proteins (CRCPress, Inc. 1997)). Variations in total chemical synthesis strategies,such as “native chemical ligation” and “expressed protein ligation” arealso standard (see, for example, Dawson et al., Science 266:776 (1994),Hackeng et al., Proc. Nat'l Acad. Sci. USA 94:7845 (1997), Dawson,Methods Enzymol. 287: 34 (1997), Muir et al, Proc. Nat'l Acad. Sci. USA95:6705 (1998), and Severinov and Muir, J. Biol. Chem. 273:16205(1998)).

Peptides and polypeptides of the present invention comprise at leastsix, at least nine, or at least 15 contiguous amino acid residues of SEQID NO:2, 5 or 21. As an illustration, polypeptides can comprise at leastsix, at least nine, or at least 15 contiguous amino acid residues of SEQID NO:2, 5 and/or 21. Within certain embodiments of the invention, thepolypeptides comprise 20, 30, 40, 50, 100, or more contiguous residuesof these amino acid sequences. Nucleic acid molecules encoding suchpeptides and polypeptides are useful as polymerase chain reactionprimers and probes.

Moreover, the polypeptides and fragments thereof of the presentinvention can be expressed as monomers, homodimers, heterodimers, ormultimers within higher eukaryotic cells. Such cells can be used toproduce IL-17RC monomeric, homodimeric, heterodimeric and multimericreceptor polypeptides that comprise at least a portion of an IL-17RCpolypeptide (“IL-17RC-comprising receptors” or “IL-17RC-comprisingreceptor polypeptides”), a portion of IL-17RC and IL-17RA together (aseither a monomer, homodimer or heterodimer) or can be used as assaycells in screening systems. Within one aspect of the present invention,a polypeptide of the present invention comprising at least theligand-binding portion of either the IL-17RC or IL-17RA extracellulardomain is produced by a cultured cell, and the cell is used to screenfor ligands for the receptor, including the natural ligand, IL-17F, aswell as IL-17A, or even agonists and antagonists of the natural ligand.To summarize this approach, a cDNA or gene encoding the receptor iscombined with other genetic elements required for its expression (e.g.,a transcription promoter), and the resulting expression vector isinserted into a host cell. Cells that express the DNA and producefunctional receptor are selected and used within a variety of screeningsystems. Each component of the monomeric, homodimeric, heterodimeric andmultimeric receptor complex can be expressed in the same cell. Moreover,the components of the monomeric, homodimeric, heterodimeric andmultimeric receptor complex can also be fused to a transmembrane domainor other membrane fusion moiety to allow complex assembly and screeningof transfectants as described above.

To assay polypeptides of the present invention, mammalian cells suitablefor use in expressing IL-17RC and IL-17RC/IL-17RA receptors or otherreceptors known to bind IL-17A or IL-17F (e.g., cells expressing IL-17R)and transducing a receptor-mediated signal include cells that expressother receptor subunits that may form a functional complex with IL-17RC.It is also preferred to use a cell from the same species as the receptorto be expressed. Within a preferred embodiment, the cell is dependentupon an exogenously supplied hematopoietic growth factor for itsproliferation. Preferred cell lines of this type are the human TF-1 cellline (ATCC number CRL-2003) and the AML-193 cell line (ATCC numberCRL-9589), which are GM-CSF-dependent human leukemic cell lines and BaF3(Palacios and Steinmetz, Cell 41: 727-734, (1985)) which is an IL-3dependent murine pre-B cell line. Other cell lines include BHK, COS-1and CHO cells. Suitable host cells can be engineered to produce thenecessary receptor subunits or other cellular component needed for thedesired cellular response. This approach is advantageous because celllines can be engineered to express receptor subunits from any species,thereby overcoming potential limitations arising from speciesspecificity. Species orthologs of the human receptor cDNA can be clonedand used within cell lines from the same species, such as a mouse cDNAin the BaF3 cell line. Cell lines that are dependent upon onehematopoietic growth factor, such as GM-CSF or IL-3, can thus beengineered to become dependent upon another cytokine that acts throughthe IL-17RC or IL-17RA receptor, such as IL-17F or IL-17A.

Cells expressing functional receptor are used within screening assays. Avariety of suitable assays are known in the art. These assays are basedon the detection of a biological response in a target cell. One suchassay is a cell proliferation assay. Cells are cultured in the presenceor absence of a test compound, and cell proliferation is detected by,for example, measuring incorporation of tritiated thymidine or bycolorimetric assay based on the metabolic breakdown of3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT)(Mosman, J. Immunol. Meth. 65: 55-63, (1983)). An alternative assayformat uses cells that are further engineered to express a reportergene. The reporter gene is linked to a promoter element that isresponsive to the receptor-linked pathway, and the assay detectsactivation of transcription of the reporter gene. A preferred promoterelement in this regard is a serum response element, or SRE. See, e.g.,Shaw et al., Cell 56:563-572, (1989). A preferred such reporter gene isa luciferase gene (de Wet et al., Mol. Cell. Biol. 7:725, (1987)).Expression of the luciferase gene is detected by luminescence usingmethods known in the art (e.g., Baumgartner et al., J. Biol. Chem.269:29094-29101, (1994); Schenborn and Goiffin, Promega Notes 41:11,1993). Luciferase activity assay kits are commercially available from,for example, Promega Corp., Madison, Wis. Target cell lines of this typecan be used to screen libraries of chemicals, cell-conditioned culturemedia, fungal broths, soil samples, water samples, and the like. Forexample, a bank of cell-conditioned media samples can be assayed on atarget cell to identify cells that produce ligand. Positive cells arethen used to produce a cDNA library in a mammalian expression vector,which is divided into pools, transfected into host cells, and expressed.Media samples from the transfected cells are then assayed, withsubsequent division of pools, re-transfection, subculturing, andre-assay of positive cells to isolate a cloned cDNA encoding the ligand.

An additional screening approach provided by the present inventionincludes the use of hybrid receptor polypeptides. These hybridpolypeptides fall into two general classes. Within the first class, theintracellular domain of IL-17RC, is joined to the ligand-binding domainof a second receptor. A second class of hybrid receptor polypeptidescomprise the extracellular (ligand-binding) domain of IL-17RC (SEQ IDNO:3) and IL-17RA (SEQ ID NO:21) with an intracellular domain of asecond receptor, preferably a hematopoietic cytokine receptor, and atransmembrane domain. Such hybrid monomers, homodimers, heterodimers andmultimers of the present invention receptors of this second class areexpressed in cells known to be capable of responding to signalstransduced by the second receptor. Together, these two classes of hybridreceptors enable the identification of a responsive cell type for thedevelopment of an assay for detecting IL-17F or IL-17A. Moreover, suchcells can be used in the presence of IL-17F or IL-17A to assay thesoluble receptor antagonists of the present invention in acompetition-type assay. In such assay, a decrease in the proliferationor signal transduction activity of IL-17F or IL-17A in the presence of asoluble receptor of the present invention demonstrates antagonisticactivity. Moreover IL-17RC-soluble receptor binding assays, ancell-based assays, can also be used to assess whether a soluble receptorbinds, blocks, inhibits, reduces, antagonizes or neutralizes IL-17F orIL-17A activity.

The present invention provides for an expression vector comprising thefollowing operably linked elements: a) a transcription promoter; b) aDNA segment encoding a polypeptide wherein the encoded polypeptidecomprises an amino acid sequence having at least 95% sequence identitywith amino acid residues 33-458 of SEQ ID NO:158, wherein the encodedpolypeptide binds IL-17A and/or IL-17F; and c) a transcriptionterminator. The DNA segment may further encode a secretory signalsequence. The DNA segment may further encode an immunoglobulin moiety,e.g., an immunoglobulin heavy chain constant region, amino acid residues459-690 of SEQ ID NO:158. The expression vector may optionally beintroduced into a cultured cell, such as E. coli, Chinese hamster ovarycell, wherein the cell expresses the polypeptide encoded by the DNAsegment. Another embodiment of the present invention is a method ofproducing a polypeptide comprising culturing a cell into which has beenintroduced an expression vector of claim 13, wherein the cell expressesthe polypeptide encoded by the DNA segment; and recovering the expressespolypeptide.

The present invention also provides a composition comprising an isolatedpolypeptide an isolated polypeptide comprising an amino acid sequencehaving at least 95% sequence identity with amino acid residues 33-458 ofSEQ ID NO:158; and a pharmaceutically acceptable carrier. Thepolypeptide may further comprises an immunoglobuline moiety (e.g.,immunoglobulin heavy chain constant region, such as an Fc region fromIgG1, IgG2, IgG3, IgG4, variants and mutants thereof; amino acidresidues 1-232 of SEQ ID NO:175, and amino acid residues 459-690 of SEQID NO:158).

The present invention also provides a method of treating a subjectsuffering from a disease caused, maintained or exascerbated by IL-17Aand/or IL-17F activity comprising administering to the subject apolypeptide comprising an amino acid sequence having at least 95%sequence identity with amino acid residues 33-458 of SEQ ID NO:158,wherein the polypeptide binds, blocks, reduces, antagonizes orneutralizes IL-17A and/or IL-17F, and wherein the disease is selectedfrom the group consisting of psoriasis, atopic and contact dermatitis,IBD, IBS, colitis, endotoxemia, arthritis, rheumatoid arthritis, Lymedisease arthritis, psoriatic arthritis, adult respiratory disease (ARD),septic shock, multiple organ failure, inflammatory lung injury such asasthma, chronic obstructive pulmonary disease (COPD), airwayhyper-responsiveness, chronic bronchitis, allergic asthma, bacterialpneumonia, psoriasis, eczema, and inflammatory bowel disease such asulcerative colitis and Crohn's disease, helicobacter pylori infection,intraabdominal adhesions and/or abscesses as results of peritonealinflammation (i.e. from infection, injury, etc.), systemic lupuserythematosus (SLE), lupus nephritis, Diabetes Type I, coronary arterydisease, stroke, multiple sclerosis, systemic sclerosis, scleroderma,nephrotic syndrome, sepsis, organ allograft rejection, graft vs. hostdisease (GVHD), transplant rejection (e.g., kidney, lung, and heart),streptococcal cell wall (SCW)-induced arthritis, osteoarthritis,gingivitis/periodontitis, herpetic stromal keratitis, osteoporosis,neuritis, cancers including prostate, renal, colon, ovarian, cervical,leukemia, cancer angiogenesis (such as ovarian cancer, cervical cancerand prostate cancer), B cell lymphoma, T cell lymphoma, cystic fibrosis,restenosis and Kawasaki disease.

F) Production of IL-17RC, IL-17RA and IL-17RC/IL-17RA Fusion Proteinsand Conjugates

One general class of IL-17RC, IL-17RA and IL-17RC/IL-17RA analogs arevariants having an amino acid sequence that is a mutation of the aminoacid sequence disclosed herein. Another general class of IL-17RC,IL-17RA and IL-17RC/IL-17RA analogs is provided by anti-idiotypeantibodies, and fragments thereof, as described below. Moreover,recombinant antibodies comprising anti-idiotype variable domains can beused as analogs (see, for example, Monfardini et al., Proc. Assoc. Am.Physicians 108:420 (1996)). Since the variable domains of anti-idiotypeIL-17RC antibodies mimic IL-17RC, these domains can provide IL-17RCbinding activity. Methods of producing anti-idiotypic catalyticantibodies are known to those of skill in the art (see, for example,Joron et al., Ann. N Y Acad. Sci. 672:216 (1992), Friboulet et al.,Appl. Biochem. Biotechnol. 47:229 (1994), and Avalle et al., Ann. N YAcad. Sci. 864:118 (1998)).

Another approach to identifying IL-17RC, IL-17RA and IL-17RC/IL-17RAanalogs is provided by the use of combinatorial libraries. Methods forconstructing and screening phage display and other combinatoriallibraries are provided, for example, by Kay et al., Phage Display ofPeptides and Proteins (Academic Press 1996), Verdine, U.S. Pat. No.5,783,384, Kay, et. al., U.S. Pat. No. 5,747,334, and Kauffman et al.,U.S. Pat. No. 5,723,323.

IL-17RC, IL-17RA and IL-17RC/IL-17RA polypeptides have both in vivo andin vitro uses. As an illustration, a soluble form of IL-17RC can beadded to cell culture medium to inhibit the effects of the IL-17RCligand (i.e. IL-17F, IL-17A or both) produced by the cultured cells.

Fusion proteins of IL-17RC, IL-17RA and IL-17RC/IL-17RA can be used toexpress and isolate the corresponding polypeptide. As described below,particular IL-17RC, IL-17RA and IL-17RC/IL-17RA fusion proteins alsohave uses in diagnosis and therapy. One type of fusion protein comprisesa peptide that guides a IL-17RC polypeptide from a recombinant hostcell. To direct a IL-17RC polypeptide into the secretory pathway of aeukaryotic host cell, a secretory signal sequence (also known as asignal peptide, a leader sequence, prepro sequence or pre sequence) isprovided in the IL-17RC expression vector. While the secretory signalsequence may be derived from IL-17RC, a suitable signal sequence mayalso be derived from another secreted protein or synthesized de novo.The secretory signal sequence is operably linked to a IL-17RC-encodingsequence such that the two sequences are joined in the correct readingframe and positioned to direct the newly synthesized polypeptide intothe secretory pathway of the host cell. Secretory signal sequences arecommonly positioned 5′ to the nucleotide sequence encoding thepolypeptide of interest, although certain secretory signal sequences maybe positioned elsewhere in the nucleotide sequence of interest (see,e.g., Welch et al., U.S. Pat. No. 5,037,743; Holland et al., U.S. Pat.No. 5,143,830).

Although the secretory signal sequence of IL-17RC, IL-17RA andIL-17RC/IL-17RA as produced by mammalian cells (e.g., tissue-typeplasminogen activator signal sequence, as described, for example, inU.S. Pat. No. 5,641,655) is useful for expression of the correspondingpolypeptide in recombinant mammalian hosts, a yeast signal sequence ispreferred for expression in yeast cells. Examples of suitable yeastsignal sequences are those derived from yeast mating phermone α-factor(encoded by the MFα1 gene), invertase (encoded by the SUC2 gene), oracid phosphatase (encoded by the PHOS gene). See, for example, Romanoset al., “Expression of Cloned Genes in Yeast,” in DNA Cloning 2: APractical Approach, 2^(nd) Edition, Glover and Hames (eds.), pages123-167 (Oxford University Press 1995).

The soluble receptor polypeptides of the present invention can beprepared by expressing a truncated DNA encoding the extracellulardomain, for example, a polypeptide which contains all or a portion SEQID NO:3, or the corresponding region of a non-human receptor. It ispreferred that the extracellular domain polypeptides be prepared in aform substantially free of transmembrane and intracellular polypeptidesegments. To direct the export of the receptor domain from the hostcell, the receptor DNA is linked to a second DNA segment encoding asecretory peptide, such as a t-PA secretory peptide. To facilitatepurification of the secreted receptor domain, a C-terminal extension,such as a poly-histidine tag, substance P, Flag™ peptide (Hopp et al.,Biotechnology 6:1204-1210, (1988); available from Eastman Kodak Co., NewHaven, Conn.) or another polypeptide or protein for which an antibody orother specific binding agent is available, can be fused to the receptorpolypeptide.

In an alternative approach, a receptor extracellular domain or portionthereof of IL-17RC, IL-17RA or IL-17RC/IL-17RA together can be expressedas a fusion with immunoglobulin heavy chain constant regions, typicallyan Fc fragment, which contains two constant region domains and a hingeregion but lacks the variable region (See Sledziewski, A Z et al., U.S.Pat. Nos. 6,018,026 and 5,750,375). The soluble polypeptides of thepresent invention include such fusions. One such fusion is shown in SEQID NO:64. Such fusions are typically secreted as multimeric moleculeswherein the Fc portions are disulfide bonded to each other and tworeceptor polypeptides are arrayed in closed proximity to each other.Fusions of this type can be used to affinity purify the cognate ligandfrom solution, as an in vitro assay tool, to block, inhibit or reducesignals in vitro by specifically titrating out ligand, and asantagonists in vivo by administering them parenterally to bindcirculating ligand and clear it from the circulation. To purify ligand,an IL-17RC, IL-17RA and IL-17RC/IL-17RA-Ig chimera is added to a samplecontaining the ligand (e.g., cell-conditioned culture media or tissueextracts) under conditions that facilitate receptor-ligand binding(typically near-physiological temperature, pH, and ionic strength). Thechimera-ligand complex is then separated by the mixture using protein A,which is immobilized on a solid support (e.g., insoluble resin beads).The ligand is then eluted using conventional chemical techniques, suchas with a salt or pH gradient. In the alternative, the chimera itselfcan be bound to a solid support, with binding and elution carried out asabove. The chimeras may be used in vivo to regulate inflammatoryresponses including acute phase responses such as serum amyloid A (SAA),C-reactive protein (CRP), and the like. Chimeras with high bindingaffinity are administered parenterally (e.g., by intramuscular,subcutaneous or intravenous injection). Circulating molecules bindligand and are cleared from circulation by normal physiologicalprocesses. For use in assays, the chimeras are bound to a support viathe F_(c) region and used in an ELISA format.

To assist in isolating polypeptides of the present invention, an assaysystem that uses a ligand-binding receptor (or an antibody, one memberof a complement/anti-complement pair) or a binding fragment thereof, anda commercially available biosensor instrument (BIAcore, PharmaciaBiosensor, Piscataway, N.J.) may be advantageously employed. Suchreceptor, antibody, member of a complement/anti-complement pair orfragment is immobilized onto the surface of a receptor chip. Use of thisinstrument is disclosed by Karlsson, J. Immunol. Methods 145:229-40,1991 and Cunningham and Wells, J. Mol. Biol. 234:554-63, 1993. Areceptor, antibody, member or fragment is covalently attached, usingamine or sulfhydryl chemistry, to dextran fibers that are attached togold film within the flow cell. A test sample is passed through thecell. If a ligand, epitope, or opposite member of thecomplement/anti-complement pair is present in the sample, it will bindto the immobilized receptor, antibody or member, respectively, causing achange in the refractive index of the medium, which is detected as achange in surface plasmon resonance of the gold film. This system allowsthe determination of on- and off-rates, from which binding affinity canbe calculated, and assessment of stoichiometry of binding.Alternatively, ligand/receptor binding can be analyzed using SELDI™technology (Ciphergen, Inc., Palo Alto, Calif.).

Ligand-binding receptor polypeptides can also be used within other assaysystems known in the art. Such systems include Scatchard analysis fordetermination of binding affinity (see Scatchard, Ann. NY Acad. Sci. 51:660-72, 1949) and calorimetric assays (Cunningham et al., Science253:545-48, 1991; Cunningham et al., Science 245:821-25, 1991).

The present invention further provides a variety of other polypeptidefusions and related multimeric proteins comprising one or morepolypeptide fusions. For example, a soluble IL-17RC, IL-17RA orIL-17RC/IL-17RA receptor polypeptide can be prepared as a fusion to adimerizing protein as disclosed in U.S. Pat. Nos. 5,155,027 and5,567,584. Preferred dimerizing proteins in this regard includeimmunoglobulin constant region domains, e.g., IgGγ1, and the human κlight chain. Immunoglobulin-soluble fusions of the present invention canbe expressed in genetically engineered cells to produce a variety ofmultimeric IL-17RC, IL-17RA or IL-17RC/IL-17RA receptor analogs.Auxiliary domains can be fused to soluble polypeptides of the presentinvention to target them to specific cells, tissues, or macromolecules(e.g., collagen, or cells expressing IL-17F or IL-17A). The polypeptidesof the present invention can be fused to two or more moieties, such asan affinity tag for purification and a targeting domain. Polypeptidefusions can also comprise one or more cleavage sites, particularlybetween domains. (See Tuan et al., Connective Tissue Research 34:1-9,1996.)

In bacterial cells, it is often desirable to express a heterologousprotein as a fusion protein to decrease toxicity, increase stability,and to enhance recovery of the expressed protein. For example, IL-17RC(or any polypeptide of the present invention) can be expressed as afusion protein comprising a glutathione S-transferase polypeptide.Glutathione S-transferease fusion proteins are typically soluble, andeasily purifiable from E. coli lysates on immobilized glutathionecolumns. In similar approaches, a IL-17RC fusion protein comprising amaltose binding protein polypeptide can be isolated with an amyloseresin column, while a fusion protein comprising the C-terminal end of atruncated Protein A gene can be purified using IgG-Sepharose.Established techniques for expressing a heterologous polypeptide as afusion protein in a bacterial cell are described, for example, byWilliams et al., “Expression of Foreign Proteins in E. coli UsingPlasmid Vectors and Purification of Specific Polyclonal Antibodies,” inDNA Cloning 2: A Practical Approach, 2^(nd) Edition, Glover and Hames(Eds.), pages 15-58 (Oxford University Press 1995). In addition,commercially available expression systems are available. For example,the PINPOINT Xa protein purification system (Promega Corporation;Madison, Wis.) provides a method for isolating a fusion proteincomprising a polypeptide that becomes biotinylated during expressionwith a resin that comprises avidin.

Peptide tags that are useful for isolating heterologous polypeptidesexpressed by either prokaryotic or eukaryotic cells includepolyHistidine tags (which have an affinity for nickel-chelating resin),c-myc tags, calmodulin binding protein (isolated with calmodulinaffinity chromatography), substance P, the RYIRS tag (which binds withanti-RYIRS antibodies), the Glu-Glu tag, and the FLAG tag (which bindswith anti-FLAG antibodies). See, for example, Luo et al., Arch. Biochem.Biophys. 329:215 (1996), Morganti et al., Biotechnol. Appl. Biochem.23:67 (1996), and Zheng et al., Gene 186:55 (1997). Nucleic acidmolecules encoding such peptide tags are available, for example, fromSigma-Aldrich Corporation (St. Louis, Mo.).

Another form of fusion protein comprises a polypeptide of the presentinvention and an immunoglobulin heavy chain constant region, typicallyan Fc fragment, which contains two or three constant region domains anda hinge region but lacks the variable region. As an illustration, Changet al., U.S. Pat. No. 5,723,125, describe a fusion protein comprising ahuman interferon and a human immunoglobulin Fc fragment. The C-terminalof the interferon is linked to the N-terminal of the Fc fragment by apeptide linker moiety. An example of a peptide linker is a peptidecomprising primarily a T cell inert sequence, which is immunologicallyinert. An exemplary peptide linker has the amino acid sequence: GGSGGSGGGG SGGGG S (SEQ ID NO:9). In this fusion protein, an illustrative Fcmoiety is a human γ4 chain, which is stable in solution and has littleor no complement activating activity. Accordingly, the present inventioncontemplates a IL-17RC or an IL-17RC/IL-17RA fusion protein thatcomprises a IL-17RC or an IL-17RC and IL-17RA moiety and a human Fcfragment, wherein the C-terminus of the IL-17RC moiety is attached tothe N-terminus of the Fc fragment via a peptide linker, such as apeptide comprising at least a portion of the amino acid sequence of SEQID NO:2, 5 or 21. Both the IL-17RC and the IL-17RA moiety can be theextracellualr domain or any fragment thereof. For example, a fusionprotein can comprise the amino acid of SEQ ID NO:3 and an Fc fragment(e.g., a human Fc fragment) (SEQ ID NO:64). Another example of such afusion protein is Variant 1454 (SEQ ID NOs: 157 and 158) which includesexons 1-6 of human IL-17RA and 8-16 of human IL-17RCx1, fused to Fc5(SEQ ID NOs: 179 and 180). Variant 1454 also has the native signalpeptide from human IL-17RA. Fc10, or any equivalent known in the art,may also be used in place of Fc5.

In another variation, a fusion protein of the present inventioncomprises an IgG sequence, an IL-17RC, IL-17RA or IL-17RC/IL-17RA moietycovalently joined to the aminoterminal end of the IgG sequence, and asignal peptide that is covalently joined to the aminoterminal of theIL-17RC or IL-17RA moiety, wherein the IgG sequence consists of thefollowing elements in the following order: a hinge region, a CH₂ domain,and a CH₃ domain. Accordingly, the IgG sequence lacks a CH₁ domain.These moieties should display a biological activity, as describedherein, such as the ability to bind with IL-17A and/or IL-17F. Thisgeneral approach to producing fusion proteins that comprise bothantibody and nonantibody portions has been described by LaRochelle etal., EP 742830 (WO 95/21258).

Fusion proteins comprising a IL-17RC or IL-17RC/IL-17RA moiety and an Fcmoiety can be used, for example, as an in vitro assay tool. For example,the presence of IL-F in a biological sample can be detected using aIL-17RC-immunoglobulin fusion protein, in which the IL-17RC moiety isused to bind the ligand, and a macromolecule, such as Protein A oranti-Fc antibody, is used to bind the fusion protein to a solid support.Such systems can be used to identify agonists and antagonists thatinterfere with the binding of a IL-17 family ligands, e.g., IL-17F orboth IL-17A and IL-17F, to their receptor.

The present invention further provides a variety of other polypeptidefusions. For example, part or all of a domain(s) conferring a desiredbiological function (eg. Binding IL-17A) can be added to a portion ofIL-17RC with the functionally equivalent domain(s) from another memberof the cytokine receptor family (i.e. IL-17RA) to create a differentmolecule (i.e. IL-17RC/IL-17RA). Polypeptide fusions can be expressed inrecombinant host cells to produce a variety of these fusion analogs. AnIL-17RC, IL-17RA or IL-17RC/IL-17RA polypeptide can be fused to two ormore moieties or domains, such as an affinity tag for purification and atargeting domain. Polypeptide fusions can also comprise one or morecleavage sites, particularly between domains. See, for example, Tuan etal., Connective Tissue Research 34:1 (1996).

Fusion proteins can be prepared by methods known to those skilled in theart by preparing each component of the fusion protein and chemicallyconjugating them. Alternatively, a polynucleotide encoding bothcomponents of the fusion protein in the proper reading frame can begenerated using known techniques and expressed by the methods describedherein. General methods for enzymatic and chemical cleavage of fusionproteins are described, for example, by Ausubel (1995) at pages 16-19 to16-25.

IL-17RC and/or IL-17RA binding domains can be further characterized byphysical analysis of structure, as determined by such techniques asnuclear magnetic resonance, crystallography, electron diffraction orphotoaffinity labeling, in conjunction with mutation of putative contactsite amino acids of ligand agonists. See, e.g., de Vos et al., Science255:306 (1992), Smith et al., J. Mol. Biol. 224:899 (1992), and Wlodaveret al., FEBS Lett. 309:59 (1992).

The present invention also contemplates chemically modified IL-17RC orIL-17RC/IL-17RA compositions, in which the polypeptide is linked with apolymer. Illustrative IL-17RC or IL-17RC/IL-17RA polypeptides aresoluble polypeptides that lack a functional transmembrane domain, suchas a polypeptide consisting of amino acid residues SEQ ID NO:3 or 21.Typically, the polymer is water soluble so that the conjugate does notprecipitate in an aqueous environment, such as a physiologicalenvironment. An example of a suitable polymer is one that has beenmodified to have a single reactive group, such as an active ester foracylation, or an aldehyde for alkylation. In this way, the degree ofpolymerization can be controlled. An example of a reactive aldehyde ispolyethylene glycol propionaldehyde, or mono-(C1-C10) alkoxy, or aryloxyderivatives thereof (see, for example, Harris, et al., U.S. Pat. No.5,252,714). The polymer may be branched or unbranched. Moreover, amixture of polymers can be used to produce IL-17RC or IL-17RC/IL-17RAconjugates.

The conjugates of the present invention used for therapy can comprisepharmaceutically acceptable water-soluble polymer moieties. Suitablewater-soluble polymers include polyethylene glycol (PEG),monomethoxy-PEG, mono-(C1-C10)alkoxy-PEG, aryloxy-PEG, poly-(N-vinylpyrrolidone)PEG, tresyl monomethoxy PEG, PEG propionaldehyde,bis-succinimidyl carbonate PEG, propylene glycol homopolymers, apolypropylene oxide/ethylene oxide co-polymer, polyoxyethylated polyols(e.g., glycerol), polyvinyl alcohol, dextran, cellulose, or othercarbohydrate-based polymers. Suitable PEG may have a molecular weightfrom about 600 to about 60,000, including, for example, 5,000, 12,000,20,000 and 25,000. A IL-17RC conjugate can also comprise a mixture ofsuch water-soluble polymers.

One example of a IL-17RC conjugate comprises a IL-17RC moiety (or anIL-17RC/IL-17RA moiety) and a polyalkyl oxide moiety attached to theN-terminus of the IL-17RC moiety. PEG is one suitable polyalkyl oxide.As an illustration, IL-17RC (or IL-17RC/IL-17RA) can be modified withPEG, a process known as “PEGylation.” PEGylation of IL-17RC can becarried out by any of the PEGylation reactions known in the art (see,for example, EP 0 154 316, Delgado et al., Critical Reviews inTherapeutic Drug Carrier Systems 9:249 (1992), Duncan and Spreafico,Clin. Pharmacokinet. 27:290 (1994), and Francis et al., Int J Hematol68:1 (1998)). For example, PEGylation can be performed by an acylationreaction or by an alkylation reaction with a reactive polyethyleneglycol molecule. In an alternative approach, IL-17RC conjugates areformed by condensing activated PEG, in which a terminal hydroxy or aminogroup of PEG has been replaced by an activated linker (see, for example,Karasiewicz et al., U.S. Pat. No. 5,382,657).

PEGylation by acylation typically requires reacting an active esterderivative of PEG with a IL-17RC or IL-17RC/IL-17RA polypeptide. Anexample of an activated PEG ester is PEG esterified toN-hydroxysuccinimide. As used herein, the term “acylation” includes thefollowing types of linkages between IL-17RC or IL-17RC/IL-17RA and awater soluble polymer: amide, carbamate, urethane, and the like. Methodsfor preparing PEGylated IL-17RC or IL-17RC/IL-17RA by acylation willtypically comprise the steps of (a) reacting a IL-17RC orIL-17RC/IL-17RA polypeptide with PEG (such as a reactive ester of analdehyde derivative of PEG) under conditions whereby one or more PEGgroups attach to IL-17RC or IL-17RC/IL-17RA, and (b) obtaining thereaction product(s). Generally, the optimal reaction conditions foracylation reactions will be determined based upon known parameters anddesired results. For example, the larger the ratio of PEG:IL-17RC (orPEG:IL-17RC/IL-17RA), the greater the percentage of polyPEGylatedIL-17RC (or IL-17RC/IL-17RA) product.

The product of PEGylation by acylation is typically a polyPEGylatedproduct, wherein the lysine &amino groups are PEGylated via an acyllinking group. An example of a connecting linkage is an amide.Typically, the resulting IL-17RC or IL-17RC/IL-17RA will be at least 95%mono-, di-, or tri-pegylated, although some species with higher degreesof PEGylation may be formed depending upon the reaction conditions.PEGylated species can be separated from unconjugated IL-17RC orIL-17RC/IL-17RA polypeptides using standard purification methods, suchas dialysis, ultrafiltration, ion exchange chromatography, affinitychromatography, and the like.

PEGylation by alkylation generally involves reacting a terminal aldehydederivative of PEG with IL-17RC or IL-17RC/IL-17RA in the presence of areducing agent. PEG groups can be attached to the polypeptide via a—CH₂—NH group.

Derivatization via reductive alkylation to produce a monoPEGylatedproduct takes advantage of the differential reactivity of differenttypes of primary amino groups available for derivatization. Typically,the reaction is performed at a pH that allows one to take advantage ofthe pKa differences between the ε-amino groups of the lysine residuesand the α-amino group of the N-terminal residue of the protein. By suchselective derivatization, attachment of a water-soluble polymer thatcontains a reactive group such as an aldehyde, to a protein iscontrolled. The conjugation with the polymer occurs predominantly at theN-terminus of the protein without significant modification of otherreactive groups such as the lysine side chain amino groups. The presentinvention provides a substantially homogenous preparation of IL-17RC orIL-17RC/IL-17RA monopolymer conjugates.

Reductive alkylation to produce a substantially homogenous population ofmonopolymer IL-17RC or IL-17RC/IL-17RA conjugate molecule can comprisethe steps of: (a) reacting a IL-17RC or IL-17RC/IL-17RA polypeptide witha reactive PEG under reductive alkylation conditions at a pH suitable topermit selective modification of the α-amino group at the amino terminusof the IL-17RC or IL-17RC/IL-17RA, and (b) obtaining the reactionproduct(s). The reducing agent used for reductive alkylation should bestable in aqueous solution and able to reduce only the Schiff baseformed in the initial process of reductive alkylation. Illustrativereducing agents include sodium borohydride, sodium cyanoborohydride,dimethylamine borane, trimethylamine borane, and pyridine borane.

For a substantially homogenous population of monopolymer IL-17RC orIL-17RC/IL-17RA conjugates, the reductive alkylation reaction conditionsare those that permit the selective attachment of the water-solublepolymer moiety to the N-terminus of IL-17RC or IL-17RC/IL-17RA. Suchreaction conditions generally provide for pKa differences between thelysine amino groups and the α-amino group at the N-terminus. The pH alsoaffects the ratio of polymer to protein to be used. In general, if thepH is lower, a larger excess of polymer to protein will be desiredbecause the less reactive the N-terminal α-group, the more polymer isneeded to achieve optimal conditions. If the pH is higher, thepolymer:IL-17RC (or polymer:IL-17RC/IL-17RA) need not be as largebecause more reactive groups are available. Typically, the pH will fallwithin the range of 3 to 9, or 3 to 6. This method can be employed formaking IL-17RC or IL-17RC/IL-17RA-comprising homodimeric, heterodimericor multimeric soluble receptor conjugates.

Another factor to consider is the molecular weight of the water-solublepolymer. Generally, the higher the molecular weight of the polymer, thefewer number of polymer molecules which may be attached to the protein.For PEGylation reactions, the typical molecular weight is about 2 kDa toabout 100 kDa, about 5 kDa to about 50 kDa, or about 12 kDa to about 25kDa. The molar ratio of water-soluble polymer to IL-17RC orIL-17RC/IL-17RA will generally be in the range of 1:1 to 100:1.Typically, the molar ratio of water-soluble polymer to IL-17RC orIL-17RC/IL-17RA will be 1:1 to 20:1 for polyPEGylation, and 1:1 to 5:1for monoPEGylation.

General methods for producing conjugates comprising a polypeptide andwater-soluble polymer moieties are known in the art. See, for example,Karasiewicz et al., U.S. Pat. No. 5,382,657, Greenwald et al., U.S. Pat.No. 5,738,846, Nieforth et al., Clin. Pharmacol. Ther. 59:636 (1996),Monkarsh et al., Anal. Biochem. 247:434 (1997)). This method can beemployed for making IL-17RC-comprising homodimeric, heterodimeric ormultimeric soluble receptor conjugates.

The present invention contemplates compositions comprising a peptide orpolypeptide, such as a soluble receptor or antibody described herein.Such compositions can further comprise a carrier. The carrier can be aconventional organic or inorganic carrier. Examples of carriers includewater, buffer solution, alcohol, propylene glycol, macrogol, sesame oil,corn oil, and the like.

G) Isolation of IL-17RC or IL-17RC/IL-17RA Polypeptides

The polypeptides of the present invention can be purified to at leastabout 80% purity, to at least about 90% purity, to at least about 95%purity, or greater than 95%, such as 96%, 97%, 98%, or greater than 99%purity with respect to contaminating macromolecules, particularly otherproteins and nucleic acids, and free of infectious and pyrogenic agents.The polypeptides of the present invention may also be purified to apharmaceutically pure state, which is greater than 99.9% pure. Incertain preparations, purified polypeptide is substantially free ofother polypeptides, particularly other polypeptides of animal origin.

Fractionation and/or conventional purification methods can be used toobtain preparations of IL-17RC or IL-17RC/IL-17RA purified from naturalsources (e.g., human tissue sources), synthetic IL-17RC orIL-17RC/IL-17RA polypeptides, and recombinant IL-17RC or IL-17RC/IL-17RApolypeptides and fusion IL-17RC or IL-17RC/IL-17RA polypeptides purifiedfrom recombinant host cells. In general, ammonium sulfate precipitationand acid or chaotrope extraction may be used for fractionation ofsamples. Exemplary purification steps may include hydroxyapatite, sizeexclusion, FPLC and reverse-phase high performance liquidchromatography. Suitable chromatographic media include derivatizeddextrans, agarose, cellulose, polyacrylamide, specialty silicas, and thelike. PEI, DEAE, QAE and Q derivatives are suitable. Exemplarychromatographic media include those media derivatized with phenyl,butyl, or octyl groups, such as Phenyl-Sepharose FF (Pharmacia),Toyopearl butyl 650 (Toso Haas, Montgomeryville, Pa.), Octyl-Sepharose(Pharmacia) and the like; or polyacrylic resins, such as Amberchrom CG71 (Toso Haas) and the like. Suitable solid supports include glassbeads, silica-based resins, cellulosic resins, agarose beads,cross-linked agarose beads, polystyrene beads, cross-linkedpolyacrylamide resins and the like that are insoluble under theconditions in which they are to be used. These supports may be modifiedwith reactive groups that allow attachment of proteins by amino groups,carboxyl groups, sulfhydryl groups, hydroxyl groups and/or carbohydratemoieties.

Examples of coupling chemistries include cyanogen bromide activation,N-hydroxysuccinimide activation, epoxide activation, sulfhydrylactivation, hydrazide activation, and carboxyl and amino derivatives forcarbodiimide coupling chemistries. These and other solid media are wellknown and widely used in the art, and are available from commercialsuppliers. Selection of a particular method for polypeptide isolationand purification is a matter of routine design and is determined in partby the properties of the chosen support. See, for example, AffinityChromatography: Principles & Methods (Pharmacia LKB Biotechnology 1988),and Doonan, Protein Purification Protocols (The Humana Press 1996).

Additional variations in IL-17RC or IL-17RC/IL-17RA isolation andpurification can be devised by those of skill in the art.

The polypeptides of the present invention can also be isolated byexploitation of particular properties. For example, immobilized metalion adsorption (IMAC) chromatography can be used to purifyhistidine-rich proteins, including those comprising polyhistidine tags.Briefly, a gel is first charged with divalent metal ions to form achelate (Sulkowski, Trends in Biochem. 3:1 (1985)). Histidine-richproteins will be adsorbed to this matrix with differing affinities,depending upon the metal ion used, and will be eluted by competitiveelution, lowering the pH, or use of strong chelating agents. Othermethods of purification include purification of glycosylated proteins bylectin affinity chromatography and ion exchange chromatography (M.Deutscher, (ed.), Meth. Enzymol. 182:529 (1990)). Within additionalembodiments of the invention, a fusion of the polypeptide of interestand an affinity tag (e.g., maltose-binding protein, an immunoglobulindomain) may be constructed to facilitate purification. Moreover, theligand-binding properties of the soluble IL-17RC or IL-17RC/IL-17RApolypeptides of the present invention can be exploited for purification,for example, of IL-17RC-comprising soluble receptors; for example, byusing affinity chromatography wherein IL-17F ligand is bound to a columnand the IL-17RC-comprising receptor is bound and subsequently elutedusing standard chromatography methods.

IL-17RC, IL-17RA or IL-17RC/IL-17RA polypeptides or fragments thereofmay also be prepared through chemical synthesis, as described above.These polypeptides may be monomers or multimers; glycosylated ornon-glycosylated; PEGylated or non-PEGylated; and may or may not includean initial methionine amino acid residue.

H) Production of Antibodies to IL-17RC or IL-17RC/IL-17RA Proteins

Antibodies to IL-17RC or IL-17RC/IL-17RA can be obtained, for example,using the product of a IL-17RC or IL-17RC/IL-17RA expression vector orIL-17RC or IL-17RC/IL-17RA isolated from a natural source as an antigen.Particularly useful anti-IL-17RC or IL-17RC/IL-17RA antibodies “bindspecifically” with IL-17RC or IL-17RC/IL-17RA. Antibodies are consideredto be specifically binding if the antibodies exhibit at least one of thefollowing two properties: (1) antibodies bind to IL-17RC orIL-17RC/IL-17RA with a threshold level of binding activity, and (2)antibodies do not significantly cross-react with polypeptides related toIL-17RC or IL-17RC/IL-17RA.

With regard to the first characteristic, antibodies specifically bind ifthey bind to a IL-17RC or IL-17RC/IL-17RA polypeptide, peptide orepitope with a binding affinity (K_(a)) of 10⁶M⁻¹ or greater, preferably10⁷ M⁻¹ or greater, more preferably 10⁸M⁻¹ or greater, and mostpreferably 10⁹ M⁻¹ or greater. The binding affinity of an antibody canbe readily determined by one of ordinary skill in the art, for example,by Scatchard analysis (Scatchard, Ann. NY Acad. Sci. 51:660 (1949)).With regard to the second characteristic, antibodies do notsignificantly cross-react with related polypeptide molecules, forexample, if they detect IL-17RC or IL-17RC/IL-17RA, but not presentlyknown polypeptides using a standard Western blot analysis. Examples ofknown related polypeptides include known cytokine receptors.

Anti-IL-17RC or IL-17RC/IL-17RA antibodies can be produced usingantigenic IL-17RC or IL-17RC/IL-17RA epitope-bearing peptides andpolypeptides. Antigenic epitope-bearing peptides and polypeptides of thepresent invention contain a sequence of at least nine, or between 15 toabout 30 amino acids contained within SEQ ID NO:2, SEQ ID NO:3, SEQ IDNO:5 or another amino acid sequence disclosed herein. However, peptidesor polypeptides comprising a larger portion of an amino acid sequence ofthe invention, containing from 30 to 50 amino acids, or any length up toand including the entire amino acid sequence of a polypeptide of theinvention, also are useful for inducing antibodies that bind withIL-17RC or IL-17RC/IL-17RA. It is desirable that the amino acid sequenceof the epitope-bearing peptide is selected to provide substantialsolubility in aqueous solvents (i.e., the sequence includes relativelyhydrophilic residues, while hydrophobic residues are typically avoided).Moreover, amino acid sequences containing proline residues may be alsobe desirable for antibody production.

As an illustration, potential antigenic sites in IL-17RC were identifiedusing the Jameson-Wolf method, Jameson and Wolf, CABIOS 4:181, (1988),as implemented by the PROTEAN program (version 3.14) of LASERGENE(DNASTAR; Madison, Wis.). Default parameters were used in this analysis.

The Jameson-Wolf method predicts potential antigenic determinants bycombining six major subroutines for protein structural prediction.Briefly, the Hopp-Woods method, Hopp et al., Proc. Nat'l Acad. Sci. USA78:3824 (1981), was first used to identify amino acid sequencesrepresenting areas of greatest local hydrophilicity (parameter: sevenresidues averaged). In the second step, Emini's method, Emini et al., J.Virology 55:836 (1985), was used to calculate surface probabilities(parameter: surface decision threshold (0.6)=1). Third, theKarplus-Schultz method, Karplus and Schultz, Naturwissenschaften 72:212(1985), was used to predict backbone chain flexibility (parameter:flexibility threshold (0.2)=1). In the fourth and fifth steps of theanalysis, secondary structure predictions were applied to the data usingthe methods of Chou-Fasman, Chou, “Prediction of Protein StructuralClasses from Amino Acid Composition,” in Prediction of Protein Structureand the Principles of Protein Conformation, Fasman (ed.), pages 549-586(Plenum Press 1990), and Garnier-Robson, Garnier et al., J. Mol. Biol.120:97 (1978) (Chou-Fasman parameters: conformation table=64 proteins; αregion threshold=103; β region threshold=105; Garnier-Robson parameters:α and β decision constants=0). In the sixth subroutine, flexibilityparameters and hydropathy/solvent accessibility factors were combined todetermine a surface contour value, designated as the “antigenic index.”Finally, a peak broadening function was applied to the antigenic index,which broadens major surface peaks by adding 20, 40, 60, or 80% of therespective peak value to account for additional free energy derived fromthe mobility of surface regions relative to interior regions. Thiscalculation was not applied, however, to any major peak that resides ina helical region, since helical regions tend to be less flexible.Hopp/Woods hydrophilicity profiles can be used to determine regions thathave the most antigenic potential within SEQ ID NO:3 (Hopp et al., Proc.Natl. Acad. Sci. 78:3824-3828, 1981; Hopp, J. Immun. Meth. 88:1-18, 1986and Triquier et al., Protein Engineering 11:153-169, 1998). The profileis based on a sliding six-residue window. Buried G, S, and T residuesand exposed H, Y, and W residues were ignored. Moreover, IL-17RCantigenic epitopes within SEQ ID NO:3 as predicted by a Jameson-Wolfplot, e.g., using DNASTAR Protean program (DNASTAR, Inc., Madison, Wis.)serve as preferred antigenic epitopes, and can be determined by one ofskill in the art. Such antigenic epitopes include (1) amino acid residue73 to amino acid residue 82 of SEQ ID NO:3; (2) amino acid residue 95 toamino acid residue 104 of SEQ ID NO:3; (3) amino acid residue 111 toamino acid residue 119 of SEQ ID NO:3; (4) amino acid residue 179 toamino acid residue 186 of SEQ ID NO:3; (5) amino acid residue 200 toamino acid residue 205 of SEQ ID NO:3; (6) amino acid residue 229 toamino acid residue 236 of SEQ ID NO:3; (7) amino acid residue 264 toamino acid residue 268 of SEQ ID NO:3; and (8) amino acid residue 275 toamino acid residue 281 of SEQ ID NO:3. The present inventioncontemplates the use of any one of antigenic peptides X to Y to generateantibodies to IL-17RC or as a tool to screen or identify neutralizingmonoclonal antibodies of the present invention. The present inventionalso contemplates polypeptides comprising at least one of antigenicpeptides X to Y. The present invention contemplates the use of anyantigenic peptides or epitopes described herein to generate antibodiesto IL-17RC, as well as to identify and screen anti-IL-17RC monoclonalantibodies that are neutralizing, and that may bind, block, inhibit,reduce, antagonize or neutralize the activity of IL-17F and IL-17A(individually or together).

Moreover, suitable antigens also include the IL-17RC or IL-17RC/IL-17RApolypeptides comprising a IL-17RC or IL-17RC/IL-17RA cytokine binding,or extracellular domain disclosed above in combination with anothercytokine extracellular domain, such as a class I or II cytokine receptordomain, such as those that may form soluble IL-17RC or IL-17RC/IL-17RAheterodimeric or multimeric polypeptides, and the like.

Polyclonal antibodies to recombinant IL-17RC or IL-17RC/IL-17RA proteinor to IL-17RC or IL-17RC/IL-17RA isolated from natural sources can beprepared using methods well-known to those of skill in the art. See, forexample, Green et al., “Production of Polyclonal Antisera,” inImmunochemical Protocols (Manson, ed.), pages 1-5 (Humana Press 1992),and Williams et al., “Expression of foreign proteins in E. coli usingplasmid vectors and purification of specific polyclonal antibodies,” inDNA Cloning 2: Expression Systems, 2nd Edition, Glover et al. (eds.),page 15 (Oxford University Press 1995). The immunogenicity of a IL-17RCor IL-17RC/IL-17RA polypeptide can be increased through the use of anadjuvant, such as alum (aluminum hydroxide) or Freund's complete orincomplete adjuvant. Polypeptides useful for immunization also includefusion polypeptides, such as fusions of IL-17RC or IL-17RC/IL-17RA or aportion thereof with an immunoglobulin polypeptide or with maltosebinding protein. The polypeptide immunogen may be a full-length moleculeor a portion thereof. If the polypeptide portion is “hapten-like,” suchportion may be advantageously joined or linked to a macromolecularcarrier (such as keyhole limpet hemocyanin (KLH), bovine serum albumin(BSA) or tetanus toxoid) for immunization.

Although polyclonal antibodies are typically raised in animals such ashorses, cows, dogs, chicken, rats, mice, rabbits, guinea pigs, goats, orsheep, an anti-IL-17RC or IL-17RC/IL-17RA antibody of the presentinvention may also be derived from a subhuman primate antibody. Generaltechniques for raising diagnostically and therapeutically usefulantibodies in baboons may be found, for example, in Goldenberg et al.,international patent publication No. WO 91/11465, and in Losman et al.,Int. J. Cancer 46:310 (1990).

Alternatively, monoclonal anti-IL-17RC or IL-17RC/IL-17RA antibodies canbe generated. Rodent monoclonal antibodies to specific antigens may beobtained by methods known to those skilled in the art (see, for example,Kohler et al., Nature 256:495 (1975), Coligan et al. (eds.), CurrentProtocols in Immunology, Vol. 1, pages 2.5.1-2.6.7 (John Wiley & Sons1991) [“Coligan”], Picksley et al., “Production of monoclonal antibodiesagainst proteins expressed in E. coli,” in DNA Cloning 2: ExpressionSystems, 2nd Edition, Glover et al. (eds.), page 93 (Oxford UniversityPress 1995)).

Briefly, monoclonal antibodies can be obtained by injecting mice with acomposition comprising a IL-17RC or IL-17RC/IL-17RA gene product,verifying the presence of antibody production by removing a serumsample, removing the spleen to obtain B-lymphocytes, fusing theB-lymphocytes with myeloma cells to produce hybridomas, cloning thehybridomas, selecting positive clones which produce antibodies to theantigen, culturing the clones that produce antibodies to the antigen,and isolating the antibodies from the hybridoma cultures.

In addition, an anti-IL-17RC or IL-17RC/IL-17RA antibody of the presentinvention may be derived from a human monoclonal antibody. Humanmonoclonal antibodies are obtained from transgenic mice that have beenengineered to produce specific human antibodies in response to antigenicchallenge. In this technique, elements of the human heavy and lightchain locus are introduced into strains of mice derived from embryonicstem cell lines that contain targeted disruptions of the endogenousheavy chain and light chain loci. The transgenic mice can synthesizehuman antibodies specific for human antigens, and the mice can be usedto produce human antibody-secreting hybridomas. Methods for obtaininghuman antibodies from transgenic mice are described, for example, byGreen et al., Nature Genet. 7:13 (1994), Lonberg et al., Nature 368:856(1994), and Taylor et al., Int. Immun. 6:579 (1994).

Monoclonal antibodies can be isolated and purified from hybridomacultures by a variety of well-established techniques. Such isolationtechniques include affinity chromatography with Protein-A Sepharose,size-exclusion chromatography, and ion-exchange chromatography (see, forexample, Coligan at pages 2.7.1-2.7.12 and pages 2.9.1-2.9.3; Baines etal., “Purification of Immunoglobulin G (IgG),” in Methods in MolecularBiology, Vol. 10, pages 79-104 (The Humana Press, Inc. 1992)).

For particular uses, it may be desirable to prepare fragments ofanti-IL-17RC or IL-17RC/IL-17RA antibodies. Such antibody fragments canbe obtained, for example, by proteolytic hydrolysis of the antibody.Antibody fragments can be obtained by pepsin or papain digestion ofwhole antibodies by conventional methods. As an illustration, antibodyfragments can be produced by enzymatic cleavage of antibodies withpepsin to provide a 5S fragment denoted F(ab′)₂. This fragment can befurther cleaved using a thiol reducing agent to produce 3.5S Fab′monovalent fragments. Optionally, the cleavage reaction can be performedusing a blocking group for the sulfhydryl groups that result fromcleavage of disulfide linkages. As an alternative, an enzymatic cleavageusing pepsin produces two monovalent Fab fragments and an Fc fragmentdirectly. These methods are described, for example, by Goldenberg, U.S.Pat. No. 4,331,647, Nisonoff et al., Arch Biochem. Biophys. 89:230(1960), Porter, Biochem. J. 73:119 (1959), Edelman et al., in Methods inEnzymology Vol. 1, page 422 (Academic Press 1967), and by Coligan atpages 2.8.1-2.8.10 and 2.10.-2.10.4.

Other methods of cleaving antibodies, such as separation of heavy chainsto form monovalent light-heavy chain fragments, further cleavage offragments, or other enzymatic, chemical or genetic techniques may alsobe used, so long as the fragments bind to the antigen that is recognizedby the intact antibody.

For example, Fv fragments comprise an association of V_(H) and V_(L)chains. This association can be noncovalent, as described by Inbar etal., Proc. Nat'l Acad. Sci. USA 69:2659 (1972). Alternatively, thevariable chains can be linked by an intermolecular disulfide bond orcross-linked by chemicals such as glutaraldehyde (see, for example,Sandhu, Crit. Rev. Biotech. 12:437 (1992)).

The Fv fragments may comprise V_(H) and V_(L) chains which are connectedby a peptide linker. These single-chain antigen binding proteins (scFv)are prepared by constructing a structural gene comprising DNA sequencesencoding the V_(H) and V_(L) domains which are connected by anoligonucleotide. The structural gene is inserted into an expressionvector which is subsequently introduced into a host cell, such as E.coli. The recombinant host cells synthesize a single polypeptide chainwith a linker peptide bridging the two V domains. Methods for producingscFvs are described, for example, by Whitlow et al., Methods: ACompanion to Methods in Enzymology 2:97 (1991) (also see, Bird et al.,Science 242:423 (1988), Ladner et al., U.S. Pat. No. 4,946,778, Pack etal., Bio/Technology 11:1271 (1993), and Sandhu, supra).

As an illustration, a scFv can be obtained by exposing lymphocytes toIL-17RC or IL-17RC/IL-17RA polypeptide in vitro, and selecting antibodydisplay libraries in phage or similar vectors (for instance, through useof immobilized or labeled IL-17RC or IL-17RC/IL-17RA protein orpeptide). Genes encoding polypeptides having potential IL-17RC orIL-17RC/IL-17RA polypeptide binding domains can be obtained by screeningrandom peptide libraries displayed on phage (phage display) or onbacteria, such as E. coli. Nucleotide sequences encoding thepolypeptides can be obtained in a number of ways, such as through randommutagenesis and random polynucleotide synthesis. These random peptidedisplay libraries can be used to screen for peptides which interact witha known target which can be a protein or polypeptide, such as a ligandor receptor, a biological or synthetic macromolecule, or organic orinorganic substances. Techniques for creating and screening such randompeptide display libraries are known in the art (Ladner et al., U.S. Pat.No. 5,223,409, Ladner et al., U.S. Pat. No. 4,946,778, Ladner et al.,U.S. Pat. No. 5,403,484, Ladner et al., U.S. Pat. No. 5,571,698, and Kayet al., Phage Display of Peptides and Proteins (Academic Press, Inc.1996)) and random peptide display libraries and kits for screening suchlibraries are available commercially, for instance from CLONTECHLaboratories, Inc. (Palo Alto, Calif.), Invitrogen Inc. (San Diego,Calif.), New England Biolabs, Inc. (Beverly, Mass.), and Pharmacia LKBBiotechnology Inc. (Piscataway, N.J.). Random peptide display librariescan be screened using the IL-17RC or IL-17RC/IL-17RA sequences disclosedherein to identify proteins which bind to IL-17RC or IL-17RC/IL-17RA.

Another form of an antibody fragment is a peptide coding for a singlecomplementarity-determining region (CDR). CDR peptides (“minimalrecognition units”) can be obtained by constructing genes encoding theCDR of an antibody of interest. Such genes are prepared, for example, byusing the polymerase chain reaction to synthesize the variable regionfrom RNA of antibody-producing cells (see, for example, Larrick et al.,Methods: A Companion to Methods in Enzymology 2:106 (1991),Courtenay-Luck, “Genetic Manipulation of Monoclonal Antibodies,” inMonoclonal Antibodies: Production, Engineering and Clinical Application,Ritter et al. (eds.), page 166 (Cambridge University Press 1995), andWard et al., “Genetic Manipulation and Expression of Antibodies,” inMonoclonal Antibodies: Principles and Applications, Birch et al.,(eds.), page 137 (Wiley-Liss, Inc. 1995)).

Alternatively, an anti-IL-17RC or IL-17RC/IL-17RA antibody may bederived from a “humanized” monoclonal antibody. Humanized monoclonalantibodies are produced by transferring mouse complementary determiningregions from heavy and light variable chains of the mouse immunoglobulininto a human variable domain. Typical residues of human antibodies arethen substituted in the framework regions of the murine counterparts.The use of antibody components derived from humanized monoclonalantibodies obviates potential problems associated with theimmunogenicity of murine constant regions. General techniques forcloning murine immunoglobulin variable domains are described, forexample, by Orlandi et al., Proc. Nat'l Acad. Sci. USA 86:3833 (1989).Techniques for producing humanized monoclonal antibodies are described,for example, by Jones et al., Nature 321:522 (1986), Carter et al.,Proc. Nat'l Acad. Sci. USA 89:4285 (1992), Sandhu, Crit. Rev. Biotech.12:437 (1992), Singer et al., J. Immun. 150:2844 (1993), Sudhir (ed.),Antibody Engineering Protocols (Humana Press, Inc. 1995), Kelley,“Engineering Therapeutic Antibodies,” in Protein Engineering Principlesand Practice, Cleland et al. (eds.), pages 399-434 (John Wiley & Sons,Inc. 1996), and by Queen et al., U.S. Pat. No. 5,693,762 (1997).

Moreover, anti-IL-17RC or IL-17RC/IL-17RA antibodies or antibodyfragments of the present invention can be PEGylated using methods in theart and described herein.

Polyclonal anti-idiotype antibodies can be prepared by immunizinganimals with anti-IL-17RC or IL-17RC/IL-17RA antibodies or antibodyfragments, using standard techniques. See, for example, Green et al.,“Production of Polyclonal Antisera,” in Methods In Molecular Biology:Immunochemical Protocols, Manson (ed.), pages 1-12 (Humana Press 1992).Also, see Coligan at pages 2.4.1-2.4.7. Alternatively, monoclonalanti-idiotype antibodies can be prepared using anti-IL-17RC orIL-17RC/IL-17RA antibodies or antibody fragments as immunogens with thetechniques, described above. As another alternative, humanizedanti-idiotype antibodies or subhuman primate anti-idiotype antibodiescan be prepared using the above-described techniques. Methods forproducing anti-idiotype antibodies are described, for example, by Irie,U.S. Pat. No. 5,208,146, Greene, et. al., U.S. Pat. No. 5,637,677, andVarthakavi and Minocha, J. Gen. Virol. 77:1875 (1996).

An anti-IL-17RC or IL-17RC/IL-17RA antibody can be conjugated with adetectable label to form an anti-IL-17RC or IL-17RC/IL-17RAimmunoconjugate. Suitable detectable labels include, for example, aradioisotope, a fluorescent label, a chemiluminescent label, an enzymelabel, a bioluminescent label or colloidal gold. Methods of making anddetecting such detectably-labeled immunoconjugates are well-known tothose of ordinary skill in the art, and are described in more detailbelow.

The detectable label can be a radioisotope that is detected byautoradiography. Isotopes that are particularly useful for the purposeof the present invention are ³H, ¹²⁵I, ¹³¹I, ³⁵S and ¹⁴C.

Anti-IL-17RC or IL-17RC/IL-17RA immunoconjugates can also be labeledwith a fluorescent compound. The presence of a fluorescently-labeledantibody is determined by exposing the immunoconjugate to light of theproper wavelength and detecting the resultant fluorescence. Fluorescentlabeling compounds include fluorescein isothiocyanate, rhodamine,phycoerytherin, phycocyanin, allophycocyanin, o-phthaldehyde andfluorescamine.

Alternatively, anti-IL-17RC or IL-17RC/IL-17RA immunoconjugates can bedetectably labeled by coupling an antibody component to achemiluminescent compound. The presence of the chemiluminescent-taggedimmunoconjugate is determined by detecting the presence of luminescencethat arises during the course of a chemical reaction. Examples ofchemiluminescent labeling compounds include luminol, isoluminol, anaromatic acridinium ester, an imidazole, an acridinium salt and anoxalate ester.

Similarly, a bioluminescent compound can be used to label anti-IL-17RCor IL-17RC/IL-17RA immunoconjugates of the present invention.Bioluminescence is a type of chemiluminescence found in biologicalsystems in which a catalytic protein increases the efficiency of thechemiluminescent reaction. The presence of a bioluminescent protein isdeter-mined by detecting the presence of luminescence. Bioluminescentcompounds that are useful for labeling include luciferin, luciferase andaequorin.

Alternatively, anti-IL-17RC or IL-17RC/IL-17RA immunoconjugates can bedetectably labeled by linking an anti-IL-17RC or IL-17RC/IL-17RAantibody component to an enzyme. When the anti-IL-17RC orIL-17RC/IL-17RA-enzyme conjugate is incubated in the presence of theappropriate substrate, the enzyme moiety reacts with the substrate toproduce a chemical moiety which can be detected, for example, byspectrophotometric, fluorometric or visual means. Examples of enzymesthat can be used to detectably label polyspecific immunoconjugatesinclude β-galactosidase, glucose oxidase, peroxidase and alkalinephosphatase.

Those of skill in the art will know of other suitable labels which canbe employed in accordance with the present invention. The binding ofmarker moieties to anti-IL-17RC or IL-17RC/IL-17RA antibodies can beaccomplished using standard techniques known to the art. Typicalmethodology in this regard is described by Kennedy et al., Clin. Chim.Acta 70:1 (1976), Schurs et al., Clin. Chim. Acta 81:1 (1977), Shih etal., Intl J. Cancer 46:1101 (1990), Stein et al., Cancer Res. 50:1330(1990), and Coligan, supra.

Moreover, the convenience and versatility of immunochemical detectioncan be enhanced by using anti-IL-17RC or IL-17RC/IL-17RA antibodies thathave been conjugated with avidin, streptavidin, and biotin (see, forexample, Wilchek et al. (eds.), “Avidin-Biotin Technology,” Methods InEnzymology, Vol. 184 (Academic Press 1990), and Bayer et al.,“Immunochemical Applications of Avidin-Biotin Technology,” in Methods InMolecular Biology, Vol. 10, Manson (ed.), pages 149-162 (The HumanaPress, Inc. 1992).

Methods for performing immunoassays are well-established. See, forexample, Cook and Self, “Monoclonal Antibodies in DiagnosticImmunoassays,” in Monoclonal Antibodies: Production, Engineering, andClinical Application, Ritter and Ladyman (eds.), pages 180-208,(Cambridge University Press, 1995), Perry, “The Role of MonoclonalAntibodies in the Advancement of Immunoassay Technology,” in MonoclonalAntibodies: Principles and Applications, Birch and Lennox (eds.), pages107-120 (Wiley-Liss, Inc. 1995), and Diamandis, Immunoassay (AcademicPress, Inc. 1996).

The present invention also contemplates kits for performing animmunological diagnostic assay for IL-17RC or IL-17RC/IL-17RA geneexpression. Such kits comprise at least one container comprising ananti-IL-17RC or IL-17RC/IL-17RA antibody, or antibody fragment. A kitmay also comprise a second container comprising one or more reagentscapable of indicating the presence of IL-17RC or IL-17RC/IL-17RAantibody or antibody fragments. Examples of such indicator reagentsinclude detectable labels such as a radioactive label, a fluorescentlabel, a chemiluminescent label, an enzyme label, a bioluminescentlabel, colloidal gold, and the like. A kit may also comprise a means forconveying to the user that IL-17RC or IL-17RC/IL-17RA antibodies orantibody fragments are used to detect IL-17RC or IL-17RC/IL-17RAprotein. For example, written instructions may state that the enclosedantibody or antibody fragment can be used to detect IL-17RC orIL-17RC/IL-17RA. The written material can be applied directly to acontainer, or the written material can be provided in the form of apackaging insert.

I) Therapeutic Uses of the IL-17RC or IL-17RC/IL-17RA Polypeptides ofthe Invention

Amino acid sequences having soluble IL-17RC or IL-17RC/IL-17RA activitycan be used to modulate the immune system by binding ligands IL-17A andIL-17F (either singly or together), and thus, preventing the binding ofthese ligands with endogenous IL-17RC and/or IL-17RA receptor. Suchantagonists, such as soluble IL-17RC or IL-17RC/IL-17RA, can also beused to modulate the immune system by inhibiting the binding of IL-17Aand/or IL-17F with the endogenous IL-17RC and/or IL-17RA receptor.Accordingly, the present invention includes the use of proteins,polypeptides, and peptides having IL-17RC or IL-17RC/IL-17RA activity(such as soluble IL-17RC or IL-17RC/IL-17RA polypeptides, IL-17RC orIL-17RA polypeptide fragments, IL-17RC or IL-17RC/IL-17RA analogs, andIL-17RC or IL-17RC/IL-17RA fusion proteins) to a subject which lacks anadequate amount of this polypeptide, or which produces an excess ofIL-17A and/or IL-17F. The polypeptides of the present invention (e.g.,soluble IL-17RC and/or IL-17RC/IL-17RA) can be also used to treat asubject which produces an excess of either IL-17A, IL-17F, IL-17RA orIL-17RC. Suitable subjects include mammals, such as humans. For example,such soluble polypeptides are useful in binding, blocking, inhibiting,reducing, antagonizing or neutralizing IL-17A and IL-17F (either singlyor together), in the treatment of inflammation and inflammatory diseasessuch as psoriasis, psoriatic arthritis, rheumatoid arthritis,endotoxemia, IBD, IBS, colitis, asthma, allograft rejection, immunemediated renal diseases, hepatobiliary diseases, multiple sclerosis,atherosclerosis, promotion of tumor growth, or degenerative jointdisease and other inflammatory conditions disclosed herein.

Within preferred embodiments, the soluble receptor comprises IL-17RC(SEQ ID NO:3) and is a monomer, homodimer, heterodimer, or multimer thatbinds to, blocks, inhibits, reduces, antagonizes or neutralizes IL-17Fand IL-17A (individually or together) in vivo. Antibodies and bindingpolypeptides to such IL-17RC monomer, homodimer, heterodimer, ormultimers also serve as antagonists of IL-17RC activity, and as IL-17Aand IL-17F antagonists (singly or together), as described herein.

Within other preferred embodiments, the soluble receptor comprisesportions both IL-17RC and IL-17RA. One such preferred embodiment is anIL-17 Variant 1454 (SEQ ID NOs: 157 and 158) which includes exons 1-6 ofhuman IL-17RA and 8-16 of human IL-17RCx1, fused to Fc5 (SEQ ID NOs: 179and 180). Variant 1454 also has the native signal peptide from humanIL-17RA. Fc10, or any equivalent known in the art, may also be used inplace of Fc5.

In addition, described herein are both polyclonal and monoclonalneutralizing anti-IL-17F antibodies bind to, block, inhibit, reduce,antagonize or neutralize IL-17F and IL-17A activity in cell basedneutralization assays. Analysis of the tissue distribution of the mRNAcorresponding IL-17RC cDNA showed that mRNA the IL-17RC gene is stronglyexpressed in thyroid, adrenal gland, prostate, and liver tissues, andexpressed to a lesser extent in heart, small intestine, stomach, andtrachea tissues. In particular, IL-17RC is consistently expressed innon-T cell peripheral blood cell lines, including monocytes, B-cells,and cells of the myeloid lineage. Also, IL-17RC mRNA is reliablyexpressed in cell lines derived from skin. Other cell lines that expressIL-17RC are all 5 of the large intestine cell lines that were present onthe array. In contrast, there is little or no expression in brain,placenta, lung, skeletal muscle, kidney, pancreas, spleen, thymus,testis, ovary, colon, peripheral blood leukocytes, spinal cord, lymphnode, and bone marrow. The ligand to which IL-17RC binds (IL-17F and/orIL-17A) is implicated in inducing inflammatory response and contributingto inflammatory diseases, primarily via its ability to enhanceproduction of inflammatory mediators, including IL-1β, IL-6 and TNF-α,as well as those mediators that are involved in the proliferation,maturation and chemotaxis of neutrophils (reviewed in Witowski et al.,Cell. Mol. Life. Sci. 61:567-579 (2004)).

Thus, particular embodiments of the present invention are directedtoward use of soluble IL-17RC and soluble IL-17RC/IL-17RA polypeptidesas antagonists in inflammatory and immune diseases or conditions such aspsoriasis, psoriatic arthritis, atopic dermatitis, inflammatory skinconditions, rheumatoid arthritis, IBD, IBS, Crohn's Disease,diverticulosis, asthma, pancreatitis, type I diabetes (IDDM), pancreaticcancer, pancreatitis, Graves Disease, colon and intestinal cancer,autoimmune disease, sepsis, organ or bone marrow transplant;inflammation due to endotoxemia, trauma, surgery or infection;amyloidosis; splenomegaly; graft versus host disease; and whereinhibition of inflammation, immune suppression, reduction ofproliferation of hematopoietic, immune, inflammatory or lymphoid cells,macrophages, T-cells (including Th1 and Th2 cells), suppression ofimmune response to a pathogen or antigen, or other instances whereinhibition of IL-17F and/or IL-17A is desired.

Moreover, soluble IL-17RC and soluble IL-17RC/IL-17RA polypeptides areuseful to:

(1) Block, inhibit, reduce, antagonize or neutralize signaling viaIL-17RA or IL-17RC in the treatment of acute inflammation, inflammationas a result of trauma, tissue injury, surgery, sepsis or infection, andchronic inflammatory diseases such as asthma, inflammatory bowel disease(IBD), IBS, chronic colitis, splenomegaly, rheumatoid arthritis,recurrent acute inflammatory episodes (e.g., tuberculosis), andtreatment of amyloidosis, and atherosclerosis, Castleman's Disease,asthma, and other diseases associated with the induction of acute-phaseresponse.

(2) Block, inhibit, reduce, antagonize or neutralize signaling IL-17RAor IL-17RC in the treatment of autoimmune diseases such as IDDM,multiple sclerosis (MS), systemic Lupus erythematosus (SLE), myastheniagravis, rheumatoid arthritis, IBS and IBD to prevent or inhibitsignaling in immune cells (e.g. lymphocytes, monocytes, leukocytes).Blocking, inhibiting, reducing, or antagonizing signaling via IL-17RCand/or IL-17RA, using the polypeptides of the present invention, mayalso benefit diseases of the pancreas, kidney, pituitary and neuronalcells. IDDM, NIDDM, pancreatitis, and pancreatic carcinoma may benefit.IL-17RC and/or IL-17RA may serve as a target for treatment of cancerwhere an antagonist of the present invention inhibits cancer growth andtargets immune-mediated killing. (Holliger P, and Hoogenboom, H: NatureBiotech. 16: 1015-1016, 1998). Soluble polypeptides of the presentinvention may also be useful to treat nephropathies such asglomerulosclerosis, membranous neuropathy, amyloidosis (which alsoaffects the kidney among other tissues), renal arteriosclerosis,glomerulonephritis of various origins, fibroproliferative diseases ofthe kidney, as well as kidney dysfunction associated with SLE, IDDM,type II diabetes (NIDDM), renal tumors and other diseases.

(3) Agonize, enhance, increase or initiate signaling via IL-17RA orIL-17RC in the treatment of autoimmune diseases such as IDDM, MS, SLE,myasthenia gravis, rheumatoid arthritis, IBS and IBD. The solublepolypeptides of the present invention may signal lymphocytes or otherimmune cells to differentiate, alter proliferation, or change productionof cytokines or cell surface proteins that ameliorate autoimmunity.Specifically, modulation of a T-helper cell response to an alternatepattern of cytokine secretion may deviate an autoimmune response toameliorate disease (Smith J A et al., J. Immunol. 160:4841 -4849, 1998).Similarly, agonistic soluble polypeptides may be used to signal, depleteand deviate immune cells involved in asthma, allergy and atopic disease.Signaling via IL-17RC and/or IL-17RA may also benefit diseases of thepancreas, kidney, pituitary and neuronal cells. IDDM, NIDDM,pancreatitis, and pancreatic carcinoma may benefit.

Soluble IL-17RC or IL-17RC/IL-17RA polypeptides described herein can beused to bind, block, inhibit, reduce, antagonize or neutralize IL-17F orIL-17A activity, either singly or together, in the treatment ofautoimmune disease, atopic disease, NIDDM, pancreatitis and kidneydysfunction as described above. A soluble form of IL-17RC orIL-17RC/IL-17RA may be used to promote an antibody response mediated byTh cells and/or to promote the production of IL-4 or other cytokines bylymphocytes or other immune cells.

The soluble polypeptides of the present invention are useful asantagonists of IL-17A and/or IL-17F. Such antagonistic effects can beachieved by direct neutralization or binding of IL-17A or IL-17F. Inaddition to antagonistic uses, the soluble receptors of the presentinvention can bind IL-17F or IL-17A and act as carrier proteins for theligand, in order to transport it to different tissues, organs, and cellswithin the body. As such, the soluble receptors of the present inventioncan be fused or coupled to molecules, polypeptides or chemical moietiesthat direct the soluble-receptor-Ligand complex to a specific site, suchas a tissue, specific immune cell, or tumor. For example, in acuteinfection or some cancers, benefit may result from induction ofinflammation and local acute phase response proteins by the action ofIL-17F. Thus, the soluble receptors of the present invention can be usedto specifically direct the action of IL-17A or IL-17F. See, Cosman, D.Cytokine 5: 95-106, 1993; and Fernandez-Botran, R. Exp. Opin. Invest.Drugs 9:497-513, 2000.

Inflammation is a protective response by an organism to fend off aninvading agent. Inflammation is a cascading event that involves manycellular and humoral mediators. On one hand, suppression of inflammatoryresponses can leave a host immunocompromised; however, if leftunchecked, inflammation can lead to serious complications includingchronic inflammatory diseases (e.g., psoriasis, arthritis, rheumatoidarthritis, multiple sclerosis, inflammatory bowel disease and the like),septic shock and multiple organ failure. Importantly, these diversedisease states share common inflammatory mediators. The collectivediseases that are characterized by inflammation have a large impact onhuman morbidity and mortality. Therefore it is clear thatanti-inflammatory proteins, such as the soluble polypeptides of thepresent invention could have crucial therapeutic potential for a vastnumber of human and animal diseases, from asthma and allergy toautoimmunity and septic shock.

1. Arthritis

Arthritis, including osteoarthritis, rheumatoid arthritis, arthriticjoints as a result of injury, and the like, are common inflammatoryconditions which would benefit from the therapeutic use ofanti-inflammatory proteins, such as the soluble polypeptides of thepresent invention. For example, rheumatoid arthritis (RA) is a systemicdisease that affects the entire body and is one of the most common formsof arthritis. It is characterized by the inflammation of the membranelining the joint, which causes pain, stiffness, warmth, redness andswelling. Inflammatory cells release enzymes that may digest bone andcartilage. As a result of rheumatoid arthritis, the inflamed jointlining, the synovium, can invade and damage bone and cartilage leadingto joint deterioration and severe pain amongst other physiologiceffects. The involved joint can lose its shape and alignment, resultingin pain and loss of movement.

Rheumatoid arthritis (RA) is an immune-mediated disease particularlycharacterized by inflammation and subsequent tissue damage leading tosevere disability and increased mortality. A variety of cytokines areproduced locally in the rheumatoid joints. Numerous studies havedemonstrated that IL-1 and TNF-alpha, two prototypic pro-inflammatorycytokines, play an important role in the mechanisms involved in synovialinflammation and in progressive joint destruction. Indeed, theadministration of TNF-alpha and IL-1 inhibitors in patients with RA hasled to a dramatic improvement of clinical and biological signs ofinflammation and a reduction of radiological signs of bone erosion andcartilage destruction. However, despite these encouraging results, asignificant percentage of patients do not respond to these agents,suggesting that other mediators are also involved in the pathophysiologyof arthritis (Gabay, Expert. Opin. Biol. Ther. 2(2):135-149, 2002). Oneof those mediators could be IL-17A or IL-17F, and as such a moleculethat binds or inhibits IL-17F or IL-17A activity, such as solubleIL-17RC or IL-17RC/IL-17RA, could serve as a valuable therapeutic toreduce inflammation in rheumatoid arthritis, and other arthriticdiseases.

There are several animal models for rheumatoid arthritis known in theart. For example, in the collagen-induced arthritis (CIA) model, micedevelop chronic inflammatory arthritis that closely resembles humanrheumatoid arthritis. Since CIA shares similar immunological andpathological features with RA, this makes it an ideal model forscreening potential human anti-inflammatory compounds. The CIA model isa well-known model in mice that depends on both an immune response, andan inflammatory response, in order to occur. The immune responsecomprises the interaction of B-cells and CD4⁺ T-cells in response tocollagen, which is given as antigen, and leads to the production ofanti-collagen antibodies. The inflammatory phase is the result of tissueresponses from mediators of inflammation, as a consequence of some ofthese antibodies cross-reacting to the mouse's native collagen andactivating the complement cascade. An advantage in using the CIA modelis that the basic mechanisms of pathogenesis are known. The relevantT-cell and B-cell epitopes on type II collagen have been identified, andvarious immunological (e.g., delayed-type hypersensitivity andanti-collagen antibody) and inflammatory (e.g., cytokines, chemokines,and matrix-degrading enzymes) parameters relating to immune-mediatedarthritis have been determined, and can thus be used to assess testcompound efficacy in the CIA model (Wooley, Curr. Opin. Rheum. 3:407-20,1999; Williams et al., Immunol. 89:9784-788, 1992; Myers et al., LifeSci. 61:1861-78, 1997; and Wang et al., Immunol. 92:8955-959, 1995).

One group has shown that an anti-mouse IL-17 antibody reduces symptomsin a mouse CIA-model relative to control mice, thus showing conceptuallythat the soluble polypeptides of the present invention would bebeneficial in treating human disease. The administration of a singlemouse-IL-17-specific rat antisera reduced the symptoms of arthritis inthe animals when introduced prophylactically or after symptoms ofarthritis were already present in the model (Lubberts et al, ArthritisRheum. 50:650-9, 2004). Therefore, IL-17RC-Fc or IL-17RC/IL-17RA-Fc canbe used to neutralize IL-17A and/or IL-17F in the treatment of specifichuman diseases such as arthritis, psoriasis, psoriatic arthritis,endotoxemia, inflammatory bowel disease (IBD), IBS, colitis, and otherinflammatory conditions disclosed herein.

The administration of the soluble polypeptides of the present invention,such as IL-17RC-Fc or other IL-17RC/IL-17RA soluble and fusion proteinsto these CIA model mice is used to evaluate their use as an antagonistto IL-17F and IL-17A to ameliorate symptoms and alter the course ofdisease. Moreover, results showing inhibition or neutralization ofIL-17F and/or IL-17A by the soluble polypeptides of the presentinvention would provide proof of concept that other IL-17A or Il-17Fantagonists can also be used to ameliorate symptoms and alter the courseof disease. Furthermore, since IL-17A and/or IL-17F induces productionof IL-1β and TNF-α, both of which are implicated in the pathogenesis andprogression of rheumatoid arthritis, the systemic or localadministration of these soluble polypeptides can potentially suppressthe inflammatory response in RA. By way of example and withoutlimitation, the injection of 10-200 ug IL-17RC-Fc per mouse (one toseven times a week for up to but not limited to 4 weeks via s.c., i.p.,or i.m route of administration) can significantly reduce the diseasescore (paw score, incident of inflammation, or disease). Depending onthe initiation of IL-17RC-Fc administration (e.g. prior to or at thetime of collagen immunization, or at any time point following the secondcollagen immunization, including those time points at which the diseasehas already progressed), IL-17RC can be efficacious in preventingrheumatoid arthritis, as well as preventing its progression. Otherpotential therapeutics include IL-17RC/IL-17RA polypeptides, and thelike.

2. Endotoxemia

Endotoxemia is a severe condition commonly resulting from infectiousagents such as bacteria and other infectious disease agents, sepsis,toxic shock syndrome, or in immunocompromised patients subjected toopportunistic infections, and the like. Therapeutically useful ofanti-inflammatory proteins, such as the soluble polypeptides of thepresent invention could aid in preventing and treating endotoxemia inhumans and animals. These soluble polypeptides could serve as a valuabletherapeutic to reduce inflammation and pathological effects inendotoxemia.

Lipopolysaccharide (LPS) induced endotoxemia engages many of theproinflammatory mediators that produce pathological effects in theinfectious diseases and LPS induced endotoxemia in rodents is a widelyused and acceptable model for studying the pharmacological effects ofpotential pro-inflammatory or immunomodulating agents. LPS, produced ingram-negative bacteria, is a major causative agent in the pathogenesisof septic shock (Glausner et al., Lancet 338:732, 1991). A shock-likestate can indeed be induced experimentally by a single injection of LPSinto animals. Molecules produced by cells responding to LPS can targetpathogens directly or indirectly. Although these biological responsesprotect the host against invading pathogens, they may also cause harm.Thus, massive stimulation of innate immunity, occurring as a result ofsevere Gram-negative bacterial infection, leads to excess production ofcytokines and other molecules, and the development of a fatal syndrome,septic shock syndrome, which is characterized by fever, hypotension,disseminated intravascular coagulation, and multiple organ failure(Dumitru et al. Cell 103:1071-1083, 2000).

These toxic effects of LPS are mostly related to macrophage activationleading to the release of multiple inflammatory mediators. Among thesemediators, TNF appears to play a crucial role, as indicated by theprevention of LPS toxicity by the administration of neutralizinganti-TNF antibodies (Beutler et al., Science 229:869, 1985). It is wellestablished that 1 ug injection of E. coli LPS into a C57B1/6 mouse willresult in significant increases in circulating IL-6, TNF-alpha, IL-1,and acute phase proteins (for example, SAA) approximately 2 hours postinjection. The toxicity of LPS appears to be mediated by these cytokinesas passive immunization against these mediators can result in decreasedmortality (Beutler et al., Science 229:869, 1985). The potentialimmunointervention strategies for the prevention and/or treatment ofseptic shock include anti-TNF mAb, IL-1 receptor antagonist, LIF, IL-10,and G-CSF.

The administration of the soluble polypeptides of the present inventionto these LPS-induced model may be used to evaluate the use of IL-17RC orIL-17RC/IL-17RA to ameliorate symptoms and alter the course ofLPS-induced disease. Moreover, results showing inhibition of IL-17F orIL-17A by these soluble polypeptides would provide proof of concept thatother such antagonists can also be used to ameliorate symptoms in theLPS-induced model and alter the course of disease. The model will showinduction of IL-17F by LPS injection and the potential treatment ofdisease by the soluble polypeptides. Since LPS induces the production ofpro-inflammatory factors possibly contributing to the pathology ofendotoxemia, the neutralization of IL-17F activity or otherpro-inflammatory factors by an antagonist soluble polyepeptide can beused to reduce the symptoms of endotoxemia, such as seen in endotoxicshock.

3. Inflammatory Bowel Disease IBD

In the United States approximately 500,000 people suffer fromInflammatory Bowel Disease (IBD) which can affect either colon andrectum (Ulcerative colitis) or both, small and large intestine (Crohn'sDisease). The pathogenesis of these diseases is unclear, but theyinvolve chronic inflammation of the affected tissues. The solublepolypeptides of the present invention could serve as a valuabletherapeutic to reduce inflammation and pathological effects in IBD, UCand related diseases.

Ulcerative colitis (UC) is an inflammatory disease of the largeintestine, commonly called the colon, characterized by inflammation andulceration of the mucosa or innermost lining of the colon. Thisinflammation causes the colon to empty frequently, resulting indiarrhea. Symptoms include loosening of the stool and associatedabdominal cramping, fever and weight loss. Although the exact cause ofUC is unknown, recent research suggests that the body's natural defensesare operating against proteins in the body which the body thinks areforeign (an “autoimmune reaction”). Perhaps because they resemblebacterial proteins in the gut, these proteins may either instigate orstimulate the inflammatory process that begins to destroy the lining ofthe colon. As the lining of the colon is destroyed, ulcers formreleasing mucus, pus and blood. The disease usually begins in the rectalarea and may eventually extend through the entire large bowel. Repeatedepisodes of inflammation lead to thickening of the wall of the intestineand rectum with scar tissue. Death of colon tissue or sepsis may occurwith severe disease. The symptoms of ulcerative colitis vary in severityand their onset may be gradual or sudden. Attacks may be provoked bymany factors, including respiratory infections or stress.

Although there is currently no cure for UC available, treatments arefocused on suppressing the abnormal inflammatory process in the colonlining. Treatments including corticosteroids immunosuppressives (e.g.,azathioprine, mercaptopurine, and methotrexate) and aminosalicytates areavailable to treat the disease. However, the long-term use ofimmunosuppressives such as corticosteroids and azathioprine can resultin serious side effects including thinning of bones, cataracts,infection, and liver and bone marrow effects. In the patients in whomcurrent therapies are not successful, surgery is an option. The surgeryinvolves the removal of the entire colon and the rectum.

There are several animal models that can partially mimic chroniculcerative colitis. The most widely used model is the2,4,6-trinitrobenesulfonic acid/ethanol (TNBS) induced colitis model,which induces chronic inflammation and ulceration in the colon. WhenTNBS is introduced into the colon of susceptible mice via intra-rectalinstillation, it induces T-cell mediated immune response in the colonicmucosa, in this case leading to a massive mucosal inflammationcharacterized by the dense infiltration of T-cells and macrophagesthroughout the entire wall of the large bowel. Moreover, thishistopathologic picture is accompanies by the clinical picture ofprogressive weight loss (wasting), bloody diarrhea, rectal prolapse, andlarge bowel wall thickening (Neurath et al. Intern. Rev. Immunol.19:51-62, 2000).

Another colitis model uses dextran sulfate sodium (DSS), which inducesan acute colitis manifested by bloody diarrhea, weight loss, shorteningof the colon and mucosal ulceration with neutrophil infiltration.DSS-induced colitis is characterized histologically by infiltration ofinflammatory cells into the lamina propria, with lymphoid hyperplasia,focal crypt damage, and epithelial ulceration. These changes are thoughtto develop due to a toxic effect of DSS on the epithelium and byphagocytosis of lamina propria cells and production of TNF-alpha andIFN-gamma. Despite its common use, several issues regarding themechanisms of DSS about the relevance to the human disease remainunresolved. DSS is regarded as a T cell-independent model because it isobserved in T cell-deficient animals such as SCID mice.

The administration of the soluble polypeptides of the present inventionto these TNBS or DSS models can be used to evaluate their use toameliorate symptoms and alter the course of gastrointestinal disease.Moreover, the results showing inhibition or neutralization of IL-17Fand/or IL-17A by these soluble polypeptides provide proof of conceptthat they (or similar molecules) can also be used to ameliorate symptomsin the colitis/IBD models and alter the course of disease.

4. Psoriasis

Psoriasis is a chronic skin condition that affects more than sevenmillion Americans. Psoriasis occurs when new skin cells grow abnormally,resulting in inflamed, swollen, and scaly patches of skin where the oldskin has not shed quickly enough. Plaque psoriasis, the most commonform, is characterized by inflamed patches of skin (“lesions”) toppedwith silvery white scales. Psoriasis may be limited to a few plaques orinvolve moderate to extensive areas of skin, appearing most commonly onthe scalp, knees, elbows and trunk. Although it is highly visible,psoriasis is not a contagious disease. The pathogenesis of the diseasesinvolves chronic inflammation of the affected tissues. The solublepolypeptides of the present invention could serve as a valuabletherapeutic to reduce inflammation and pathological effects inpsoriasis, other inflammatory skin diseases, skin and mucosal allergies,and related diseases.

Psoriasis is a T-cell mediated inflammatory disorder of the skin thatcan cause considerable discomfort. It is a disease for which there is nocure and affects people of all ages. Psoriasis affects approximately twopercent of the populations of European and North America. Althoughindividuals with mild psoriasis can often control their disease withtopical agents, more than one million patients worldwide requireultraviolet or systemic immunosuppressive therapy. Unfortunately, theinconvenience and risks of ultraviolet radiation and the toxicities ofmany therapies limit their long-term use. Moreover, patients usuallyhave recurrence of psoriasis, and in some cases rebound, shortly afterstopping immunosuppressive therapy.

The soluble polypeptides of the present invention may also be usedwithin diagnostic systems for the detection of circulating levels ofIL-17F or IL-17A, and in the detection of IL-17F or IL-17A associatedwith acute phase inflammatory response. Within a related embodiment, thesoluble polypeptides of the present invention can be used to detectcirculating or locally-acting IL-17F or IL-17A polypeptides. Elevated ordepressed levels of ligand or receptor polypeptides may be indicative ofpathological conditions, including inflammation or cancer. IL-17F isknown to induce associated acute phase inflammatory response. Moreover,detection of acute phase proteins or molecules such as IL-17A or IL-17Fcan be indicative of a chronic inflammatory condition in certain diseasestates (e.g., asthma, psoriasis, rheumatoid arthritis, colitis, IBD,IBS). Detection of such conditions serves to aid in disease diagnosis aswell as help a physician in choosing proper therapy.

In addition to other disease models described herein, the activity ofthe soluble polypeptides of the present invention on inflammatory tissuederived from human psoriatic lesions can be measured in vivo using asevere combined immune deficient (SCID) mouse model. Several mousemodels have been developed in which human cells are implanted intoimmunodeficient mice (collectively referred to as xenograft models);see, for example, Cattan A R, Douglas E, Leuk. Res. 18:513-22, 1994 andFlavell, D J, Hematological Oncology 14:67-82, 1996. As an in vivoxenograft model for psoriasis, human psoriatic skin tissue is implantedinto the SCID mouse model, and challenged with an appropriateantagonist. Moreover, other psoriasis animal models in their art may beused to evaluate IL-17A and IL-17F antagonists, such as human psoriaticskin grafts implanted into AGR129 mouse model, and challenged with anappropriate antagonist (e.g., see, Boyman, O. et al., J. Exp. Med.Online publication #20031482, 2004, incorporated herein by reference).The soluble polypeptides of the present invention that bind, block,inhibit, reduce, antagonize or neutralize the activity of IL-17F or bothIL-17A and IL-17F are preferred antagonists, as well as other IL-17A andIL-17F antagonists can be used in this model. Similarly, tissues orcells derived from human colitis, IBD, IBS, arthritis, or otherinflammatory lesions can be used in the SCID model to assess theanti-inflammatory properties of the IL-17A and IL-17F antagonistsdescribed herein.

Therapies designed to abolish, retard, or reduce inflammation using thesoluble polypeptides of the present invention can be tested byadministration to SCID mice bearing human inflammatory tissue (e.g.,psoriatic lesions and the like), or other models described herein.Efficacy of treatment is measured and statistically evaluated asincreased anti-inflammatory effect within the treated population overtime using methods well known in the art. Some exemplary methodsinclude, but are not limited to measuring for example, in a psoriasismodel, epidermal thickness, the number of inflammatory cells in theupper dermis, and the grades of parakeratosis. Such methods are known inthe art and described herein. For example, see Zeigler, M. et al. LabInvest 81:1253, 2001; Zollner, T. M. et al. J. Clin. Invest. 109:671,2002; Yamanaka, N. et al. Microbiol. Immunol. 45:507, 2001;Raychaudhuri, S. P. et al. Br. J. Dermatol. 144:931, 2001; Boehncke, W.H et al. Arch. Dermatol. Res. 291:104, 1999; Boehncke, W. H et al. J.Invest. Dermatol. 116:596, 2001; Nickoloff, B. J. et al. Am. J. Pathol.146:580, 1995; Boehncke, W. H et al. J. Cutan. Pathol. 24:1, 1997;Sugai, J., M. et al. J. Dermatol. Sci. 17:85, 1998; and Villadsen L. S.et al. J. Clin. Invest. 112:1571, 2003. Inflammation may also bemonitored over time using well-known methods such as flow cytometry (orPCR) to quantitate the number of inflammatory or lesional cells presentin a sample, score (weight loss, diarrhea, rectal bleeding, colonlength) for IBD, paw disease score and inflammation score for CIA RAmodel. For example, therapeutic strategies appropriate for testing insuch a model include direct treatment using soluble IL-17RC orIL-17RC/IL-17RA, or other IL-17A and IL-17F antagonists (singly ortogether), or related conjugates or antagonists based on the disruptinginteraction of IL-17RC and/or IL-17RA with their corresponding ligands.

Psoriasis is a chronic inflammatory skin disease that is associated withhyperplastic epidermal keratinocytes and infiltrating mononuclear cells,including CD4⁺ memory T cells, neutrophils and macrophages(Christophers, Int. Arch. Allergy Immunol., 110:199, 1996). It iscurrently believed that environmental antigens play a significant rolein initiating and contributing to the pathology of the disease. However,it is the loss of tolerance to self-antigens that is thought to mediatethe pathology of psoriasis. Dendritic cells and CD4⁺ T cells are thoughtto play an important role in antigen presentation and recognition thatmediate the immune response leading to the pathology. We have recentlydeveloped a model of psoriasis based on the CD4+ CD45RB transfer model(Davenport et al., Internat. Immunopharmacol., 2:653-672). The solublepolypeptides of the present invention are administered to the mice.Inhibition of disease scores (skin lesions, inflammatory cytokines)indicates the effectiveness of those soluble polypeptides in psoriasis.

5. Atopic Dermatitis.

AD is a common chronic inflammatory disease that is characterized byhyperactivated cytokines of the helper T cell subset 2 (Th2). Althoughthe exact etiology of AD is unknown, multiple factors have beenimplicated, including hyperactive Th2 immune responses, autoimmunity,infection, allergens, and genetic predisposition. Key features of thedisease include xerosis (dryness of the skin), pruritus (itchiness ofthe skin), conjunctivitis, inflammatory skin lesions, Staphylococcusaureus infection, elevated blood eosinophilia, elevation of serum IgEand IgG1, and chronic dermatitis with T cell, mast cell, macrophage andeosinophil infiltration. Colonization or infection with S. aureus hasbeen recognized to exacerbate AD and perpetuate chronicity of this skindisease.

AD is often found in patients with asthma and allergic rhinitis, and isfrequently the initial manifestation of allergic disease. About 20% ofthe population in Western countries suffer from these allergic diseases,and the incidence of AD in developed countries is rising for unknownreasons. AD typically begins in childhood and can often persist throughadolescence into adulthood. Current treatments for AD include topicalcorticosteroids, oral cyclosporin A, non-corticosteroidimmunosuppressants such as tacrolimus (FK506 in ointment form), andinterferon-gamma. Despite the variety of treatments for AD, manypatients' symptoms do not improve, or they have adverse reactions tomedications, requiring the search for other, more effective therapeuticagents. The soluble polypeptides of the present invention can be used toneutralize IL-17F and IL-17A in the treatment of specific human diseasessuch as atopic dermatitis, inflammatory skin conditions, and otherinflammatory conditions disclosed herein.

6. Asthma

IL-17 plays an important role in allergen-induced T cell activation andneutrophilic influx in the airways. The receptor for IL-17 is expressedin the airways (Yao et al., Immunity 3:811 (1995)) and IL-17 mediatedneutrophil recruitment in allergic asthma is largely induced by thechemoattractant IL-8, GRO-α and macrophage inflammatory protein-2(MIP-2) produced by IL-17 stimulated human bronchial epithelial cells(HBECs) and human bronichial fibroblasts (Yao et al., J Immunol 155:5483(1995)); Molet et al., J Allergy Clin Immunol 108:430 (2001)). IL-17also stimulates HBECs to release IL-6, a neutrophil-activating factor(Fossiez et al., J Exp Med 183:2593 (1996), and Linden et al., Int ArchAllergy Immunol 126:179 (2001)) and has been shown to synergize withTNF-α, to prolong the survival of human neutrophils in vitro (Laan etal., Eur Respir J 21:387 (2003)). Moreover, IL-17 is capable ofamplifying the inflammatory responses in asthma by its ability toenhance the secretion of cytokines implicated in airway remodeling suchas the profibrotic cytokines, IL-6 and IL-11 and inflammatory mediatorsgranulocyte colony-stimulating factor (G-CSF) and granulocyte macrophagecolony-stimulating factor (GM-CSF) (Molet et al., J Allergy Clin Immunol108:430 (2001)).

Clinical evidence shows that acute, severe exacerbations of asthma areassociated with recruitment and activation of neutrophils in theairways, thus IL-17 is likely to play a significant role in asthma.Patients with mild asthma display a detectable increase in the localconcentration of free, soluble IL-17A protein (Molet et al., J AllergyClin Immunol 108:430 (2001)) while healthy human volunteers withinduced, severe airway inflammation due to the exposure to a swineconfinement, display a pronounced increase in the concentration of free,soluble IL-17A protein in the bronchoalveolar space (Fossiez et al., JExp Med 183:2593 (1996), and Linden et al., Int Arch Allergy Immunol126:179 (2001)). Furthermore, IL-17 levels in sputum have correlatedwith individuals who have increased airway hyper-reactivity Barczyk etal., Respir Med 97:726 (2003).

In animal models of airway hyper-responsiveness, chronic inhalation ofovalbumin by sensitized mice resulted in bronchial eosinophilicinflammation and early induction of IL-17 mRNA expression in inflamedlung tissue, together with a bronchial neutrophilia. (Hellings et al.,Am J Respir Cell Mol Biol 28:42 (2003).) Anti-IL-17 monoclonalantibodies strongly reduced bronchial neutrophilic influx butsignificantly enhanced IL-5 levels in both bronchoalveolar lavage fluidand serum, and aggravated allergen-induced bronchial eosinophilicinflux, suggesting that IL-17A may be involved in determining thebalance between neutrophil and eosinophil accumulation following antigeninsult. (Id.)

Among the IL-17 family members, IL-17F is most closely related toIL-17A. The biological activities mediated by IL-17F are similar tothose of IL-17A, where IL-17F stimulates production of IL-6, IL-8 andG-CSF. (Hurst et al., J Immunol 169:443 (2002).) IL-17F also inducesproduction of IL-2, transforming growth factor (TGF)-13, and monocytechemoattractant protein (MCP) in endothelial cells. (Starnes et al., JImmunol 167:4137 (2001).) Similarly, allergen challenge can increaselocal IL-17F in patients with allergic asthma. (Kawaguchi et al., JImmunol 167:4430 (2001).) Gene delivery of IL-17F in murine lungincreases neutrophils in the bronchoalveolar space, while mucosaltransfer of the IL-17F gene enhances the levels of Ag-induced pulmonaryneutrophilia and airway responsiveness to methacholine. (Oda et al., AmJ Respir Crit. Care Med 171:12 (2005).)

Apart from asthma, several chronic inflammatory airway diseases arecharacterized by neutrophil recruitment in the airways and IL-17 hasbeen reported to play an important role in the pathogenesis ofrespiratory conditions such as chronic obstructive pulmonary disease(COPD), bacterial pneumonia and cystic fibrosis (Linden et al., EurRespir J 15:973 (2000); Ye et al., Am J Respir Cell Mol Biol 25:335(2001); Rahman et al., Clin Immunol 115:268 (2005)). An anti-IL-17Aand/or anti-IL-17F therapeutic molecule could be demonstrated to beefficacious for chronic inflammatory airway disease in an in vitro modelof inflammation. The ability of antagonists to IL-17F and/or IL-17Aactivity, such as IL-17RC soluble receptors and antibodies theretoincluding the anti-human-IL-17RC monoclonal and neutralizing antibodiesof the present invention to inhibit IL-17A or and/or IL-17F-inducedcytokine and chemokine production from cultured HBECs or bronchialfibroblasts could be used as a measure of efficacy for such antagonistsin the prevention of the production of inflammatory mediators directlyresulting from IL-17A and/or F stimulation. If the addition ofantagonists, such as the soluble polypeptides of the present invention,to IL-17F and/or IL-17A activity, markedly reduces the production andexpression of inflammatory mediators, it would be expected to beefficacious in inflammatory aspects associated with chronic airwayinflammation.

7. Irritable Bowel Syndrome (“IBS”)

Irritable bowel syndrome represents a disease characterized by abdominalpain or discomfort and an erratic bowel habit. IBS patients can becharacterized into three main groups based on bowel habits: those withpredominantly loose or frequent stools, those with predominantly hard orinfrequent stools, and those with variable or normal stools (Talley etal., 2002). Altered intestinal motility, abnormalities in epithelialfunction, abnormal transit of stool and gas, and stress, may contributeto symptoms, while visceral hypersensitivity is a key feature in mostpatients. Genetic factors affecting pain-signaling and disturbances incentral processing of afferent signals are postulated to predisposeindividuals to IBS following specific environmental exposures. Studieshave also demonstrated that inflammatory responses in the colon maycontribute to increased sensitivity of smooth muscle and enteric nervesand therefore perturb sensory-motor functions in the intestine (Collinset al., 2001). There is clinical overlap between IBS and IBD, withIBS-like symptoms frequently reported in patients before the diagnosisof IBD, and a higher than expected IBS symptoms in patients in remissionfrom established IBD. Thus, these conditions may coexist with a higherthan expected frequency, or may exist on a continuum, with IBS and IBDat different ends of the same spectrum. However, it should be noted thatin most IBS patients, colonic biopsy specimens appear normal.Nevertheless, IBS significantly affects a very large number ofindividuals (U.S. prevalence in 2000, approximately 16 millionindividuals), resulting in a total cost burden of 1.7 billion dollars(year 2000). Thus, among the most prevalent and costly gastrointestinaldiseases and disorders, IBS is second only to gastroesophageal refluxdisease (GERD). Yet unlike GERD, treatment for IBS remainsunsatisfactory (Talley et al., 2002; Farhadi et al., 2001; Collins etal., 2001), demonstrating that IBS clearly represents an unmet medicalneed.

Converging disease models have been proposed that postulate an enhancedresponsiveness of neural, immune or neuroimmune circuits in the centralnervous system (CNS) or in the gut to central (psychosocial) orperipheral (tissue irritation, inflammation, infection) perturbations ofnormal homeostasis (Talley et al., 2002). This enhanced responsivenessresults in dysregulation of gut motility, epithelial function (immune,permeability), and visceral hypersensitivity, which in turn results inIBS symptoms.

There may be a role for a number of different molecules in thepathogenesis of IBS including a role for molecules that stimulateneurons and those that are involved in initiation of inflammatoryprocess. A number of our in-house molecules are known to be linked topossible activity on neurons due to their direct expression by neuronsor expression of their receptors on neurons, including IL-17D, IL-17Band IL-31. Moreover, a number of IL-17 family members and relatedmolecules have been associated with inflammation in the gut, includingIL-17A, IL-17F, IL-23 and IL-31.

Efficacy of inhibitors of these molecules could be tested in vivo inanimal models of disease. Several animal models have been proposed thatmimic key features of IBS and involve centrally targeted stimuli(stress) or peripherally targeted stimuli (infection, inflammation). Twoexamples of in vivo animal models that can be used to determine theeffectiveness of inhibitors in the treatment of IBS are (i) modelsfocusing on primary CNS-directed pathogeneisis of IBS (stress models),and (ii) models focusing on gut-directed inducers of stress (i.e. gutinflammation, infection or physical stress). It should be noted however,that events within the CNS or in the gastrointestinal (GI) tract do notoccur in isolation and that symptoms of IBS most likely result from acomplex interaction between signals from the CNS on the GI and viceversa.

J) Pharmaceutical Formulations

For pharmaceutical use, the soluble polypeptides of the presentinvention are formulated for parenteral, particularly intravenous orsubcutaneous, delivery according to conventional methods. Intravenousadministration will be by bolus injection, controlled release, e.g.,using mini-pumps or other appropriate technology, or by infusion over atypical period of one to several hours. In general, pharmaceuticalformulations will include a hematopoietic protein in combination with apharmaceutically acceptable carrier, such as saline, buffered saline, 5%dextrose in water or the like. Formulations may further include one ormore excipients, preservatives, solubilizers, buffering agents, albuminto prevent protein loss on vial surfaces, etc. When utilizing such acombination therapy, the cytokines may be combined in a singleformulation or may be administered in separate formulations. Methods offormulation are well known in the art and are disclosed, for example, inRemington's Pharmaceutical Sciences, Gennaro, ed., Mack Publishing Co.,Easton Pa., 1990, which is incorporated herein by reference. Therapeuticdoses will generally be in the range of 0.1 to 100 mg/kg of patientweight per day, preferably 0.5-20 mg/kg per day, with the exact dosedetermined by the clinician according to accepted standards, taking intoaccount the nature and severity of the condition to be treated, patienttraits, etc. Determination of dose is within the level of ordinary skillin the art. The proteins will commonly be administered over a period ofup to 28 days following chemotherapy or bone-marrow transplant or untila platelet count of >20,000/mm³, preferably >50,000/mm³, is achieved.More commonly, the proteins will be administered over one week or less,often over a period of one to three days. In general, a therapeuticallyeffective amount of the soluble polypeptides of the present invention inan amount sufficient to produce a clinically significant increase in theproliferation and/or differentiation of lymphoid or myeloid progenitorcells, which will be manifested as an increase in circulating levels ofmature cells (e.g. platelets or neutrophils). Treatment of plateletdisorders will thus be continued until a platelet count of at least20,000/mm³, preferably 50,000/mm³, is reached. The soluble polypeptidesof the present invention can also be administered in combination withother cytokines such as IL-3, -6 and -11; stem cell factor;erythropoietin; G-CSF and GM-CSF. Within regimens of combinationtherapy, daily doses of other cytokines will in general be: EPO, 150U/kg; GM-CSF, 5-15 lg/kg; IL-3, 1-5 lg/kg; and G-CSF, 1-25 lg/kg.Combination therapy with EPO, for example, is indicated in anemicpatients with low EPO levels.

Generally, the dosage of administered soluble polypeptides will varydepending upon such factors as the patient's age, weight, height, sex,general medical condition and previous medical history. Typically, it isdesirable to provide the recipient with a dosage of such solublepolypeptide which is in the range of from about 1 pg/kg to 10 mg/kg(amount of agent/body weight of patient), although a lower or higherdosage also may be administered as circumstances dictate.

Administration of the soluble polypeptides of the present invention to asubject can be intravenous, intraarterial, intraperitoneal,intramuscular, subcutaneous, intrapleural, intrathecal, by perfusionthrough a regional catheter, or by direct intralesional injection. Whenadministering therapeutic proteins by injection, the administration maybe by continuous infusion or by single or multiple boluses.

Additional routes of administration include oral, mucosal-membrane,pulmonary, and transcutaneous. Oral delivery is suitable for polyestermicrospheres, zein microspheres, proteinoid microspheres,polycyanoacrylate microspheres, and lipid-based systems (see, forexample, DiBase and Morrel, “Oral Delivery of MicroencapsulatedProteins,” in Protein Delivery: Physical Systems, Sanders and Hendren(eds.), pages 255-288 (Plenum Press 1997)). The feasibility of anintranasal delivery is exemplified by such a mode of insulinadministration (see, for example, Hinchcliffe and Ilium, Adv. DrugDeliv. Rev. 35:199 (1999)). Dry or liquid particles comprising solubleIL-17RC or anti-IL-17RC antibodies can be prepared and inhaled with theaid of dry-powder dispersers, liquid aerosol generators, or nebulizers(e.g., Pettit and Gombotz, TIBTECH 16:343 (1998); Patton et al., Adv.Drug Deliv. Rev. 35:235 (1999)). This approach is illustrated by theAERX diabetes management system, which is a hand-held electronic inhalerthat delivers aerosolized insulin into the lungs. Studies have shownthat proteins as large as 48,000 kDa have been delivered across skin attherapeutic concentrations with the aid of low-frequency ultrasound,which illustrates the feasibility of trascutaneous administration(Mitragotri et al., Science 269:850 (1995)). Transdermal delivery usingelectroporation provides another means to administer the solublepolypeptides of the present invention (Potts et al., Pharm. Biotechnol.10:213 (1997)).

A pharmaceutical composition comprising the soluble polypeptides of thepresent invention can be formulated according to known methods toprepare pharmaceutically useful compositions, whereby the therapeuticproteins are combined in a mixture with a pharmaceutically acceptablecarrier. A composition is said to be a “pharmaceutically acceptablecarrier” if its administration can be tolerated by a recipient patient.Sterile phosphate-buffered saline is one example of a pharmaceuticallyacceptable carrier. Other suitable carriers are well-known to those inthe art. See, for example, Gennaro (ed.), Remington's PharmaceuticalSciences, 19th Edition (Mack Publishing Company 1995).

For purposes of therapy, the soluble polypeptides of the presentinvention and a pharmaceutically acceptable carrier are administered toa patient in a therapeutically effective amount. A combination of atherapeutic molecule of the present invention and a pharmaceuticallyacceptable carrier is said to be administered in a “therapeuticallyeffective amount” if the amount administered is physiologicallysignificant. An agent is physiologically significant if its presenceresults in a detectable change in the physiology of a recipient patient.For example, an agent used to treat inflammation is physiologicallysignificant if its presence alleviates the inflammatory response.

A pharmaceutical composition comprising a soluble polypeptide of thepresent invention can be furnished in liquid form, in an aerosol, or insolid form. Liquid forms, are illustrated by injectable solutions andoral suspensions. Exemplary solid forms include capsules, tablets, andcontrolled-release forms. The latter form is illustrated by miniosmoticpumps and implants (Bremer et al., Pharm. Biotechnol. 10:239 (1997);Ranade, “Implants in Drug Delivery,” in Drug Delivery Systems, Ranadeand Hollinger (eds.), pages 95-123 (CRC Press 1995); Bremer et al.,“Protein Delivery with Infusion Pumps,” in Protein Delivery: PhysicalSystems, Sanders and Hendren (eds.), pages 239-254 (Plenum Press 1997);Yewey et al., “Delivery of Proteins from a Controlled Release InjectableImplant,” in Protein Delivery: Physical Systems, Sanders and Hendren(eds.), pages 93-117 (Plenum Press 1997)).

Liposomes provide one means to deliver therapeutic polypeptides to asubject intravenously, intraperitoneally, intrathecally,intramuscularly, subcutaneously, or via oral administration, inhalation,or intranasal administration. Liposomes are microscopic vesicles thatconsist of one or more lipid bilayers surrounding aqueous compartments(see, generally, Bakker-Woudenberg et al., Eur. J. Clin. Microbiol.Infect. Dis. 12 (Suppl. 1):561 (1993), Kim, Drugs 46:618 (1993), andRanade, “Site-Specific Drug Delivery Using Liposomes as Carriers,” inDrug Delivery Systems, Ranade and Hollinger (eds.), pages 3-24 (CRCPress 1995)). Liposomes are similar in composition to cellular membranesand as a result, liposomes can be administered safely and arebiodegradable. Depending on the method of preparation, liposomes may beunilamellar or multilamellar, and liposomes can vary in size withdiameters ranging from 0.02 μm to greater than 10 μm. A variety ofagents can be encapsulated in liposomes: hydrophobic agents partition inthe bilayers and hydrophilic agents partition within the inner aqueousspace(s) (see, for example, Machy et al., Liposomes In Cell Biology AndPharmacology (John Libbey 1987), and Ostro et al., American J. Hosp.Pharm. 46:1576 (1989)). Moreover, it is possible to control thetherapeutic availability of the encapsulated agent by varying liposomesize, the number of bilayers, lipid composition, as well as the chargeand surface characteristics of the liposomes.

Liposomes can adsorb to virtually any type of cell and then slowlyrelease the encapsulated agent. Alternatively, an absorbed liposome maybe endocytosed by cells that are phagocytic. Endocytosis is followed byintralysosomal degradation of liposomal lipids and release of theencapsulated agents (Scherphof et al., Ann. N.Y. Acad. Sci. 446:368(1985)). After intravenous administration, small liposomes (0.1 to 1.0μm) are typically taken up by cells of the reticuloendothelial system,located principally in the liver and spleen, whereas liposomes largerthan 3.0 μm are deposited in the lung. This preferential uptake ofsmaller liposomes by the cells of the reticuloendothelial system hasbeen used to deliver chemotherapeutic agents to macrophages and totumors of the liver.

The reticuloendothelial system can be circumvented by several methodsincluding saturation with large doses of liposome particles, orselective macrophage inactivation by pharmacological means (Claassen etal., Biochim. Biophys. Acta 802:428 (1984)). In addition, incorporationof glycolipid- or polyethelene glycol-derivatized phospholipids intoliposome membranes has been shown to result in a significantly reduceduptake by the reticuloendothelial system (Allen et al., Biochim.Biophys. Acta 1068:133 (1991); Allen et al., Biochim. Biophys. Acta1150:9 (1993)).

Liposomes can also be prepared to target particular cells or organs byvarying phospholipid composition or by inserting receptors or ligandsinto the liposomes. For example, liposomes, prepared with a high contentof a nonionic surfactant, have been used to target the liver (Hayakawaet al., Japanese Patent 04-244,018; Kato et al., Biol. Pharm. Bull.16:960 (1993)). These formulations were prepared by mixing soybeanphospatidylcholine, α-tocopherol, and ethoxylated hydrogenated castoroil (HCO-60) in methanol, concentrating the mixture under vacuum, andthen reconstituting the mixture with water. A liposomal formulation ofdipalmitoylphosphatidylcholine (DPPC) with a soybean-derivedsterylglucoside mixture (SG) and cholesterol (Ch) has also been shown totarget the liver (Shimizu et al., Biol. Pharm. Bull. 20:881 (1997)).

Alternatively, various targeting ligands can be bound to the surface ofthe liposome, such as antibodies, antibody fragments, carbohydrates,vitamins, and transport proteins. For example, liposomes can be modifiedwith branched type galactosyllipid derivatives to targetasialoglycoprotein (galactose) receptors, which are exclusivelyexpressed on the surface of liver cells (Kato and Sugiyama, Crit. Rev.Ther. Drug Carrier Syst. 14:287 (1997); Murahashi et al., Biol. Pharm.Bull. 20:259 (1997)). Similarly, Wu et al., Hepatology 27:772 (1998),have shown that labeling liposomes with asialofetuin led to a shortenedliposome plasma half-life and greatly enhanced uptake ofasialofetuin-labeled liposome by hepatocytes. On the other hand, hepaticaccumulation of liposomes comprising branched type galactosyllipidderivatives can be inhibited by preinjection of asialofetuin (Murahashiet al., Biol. Pharm. Bull. 20:259 (1997)). Polyaconitylated human serumalbumin liposomes provide another approach for targeting liposomes toliver cells (Kamps et al., Proc. Nat'l Acad. Sci. USA 94:11681 (1997)).Moreover, Geho, et al. U.S. Pat. No. 4,603,044, describe ahepatocyte-directed liposome vesicle delivery system, which hasspecificity for hepatobiliary receptors associated with the specializedmetabolic cells of the liver.

In a more general approach to tissue targeting, target cells areprelabeled with biotinylated antibodies specific for a ligand expressedby the target cell (Harasym et al., Adv. Drug Deliv. Rev. 32:99 (1998)).After plasma elimination of free antibody, streptavidin-conjugatedliposomes are administered. In another approach, targeting antibodiesare directly attached to liposomes (Harasym et al., Adv. Drug Deliv.Rev. 32:99 (1998)).

Polypeptides and antibodies can be encapsulated within liposomes usingstandard techniques of protein microencapsulation (see, for example,Anderson et al., Infect. Immun. 31:1099 (1981), Anderson et al., CancerRes. 50:1853 (1990), and Cohen et al., Biochim. Biophys. Acta 1063:95(1991), Alving et al. “Preparation and Use of Liposomes in ImmunologicalStudies,” in Liposome Technology, 2nd Edition, Vol. III, Gregoriadis(ed.), page 317 (CRC Press 1993), Wassef et al., Meth. Enzymol. 149:124(1987)). As noted above, therapeutically useful liposomes may contain avariety of components. For example, liposomes may comprise lipidderivatives of poly(ethylene glycol) (Allen et al., Biochim. Biophys.Acta 1150:9 (1993)).

Degradable polymer microspheres have been designed to maintain highsystemic levels of therapeutic proteins. Microspheres are prepared fromdegradable polymers such as poly(lactide-co-glycolide) (PLG),polyanhydrides, poly (ortho esters), nonbiodegradable ethylvinyl acetatepolymers, in which proteins are entrapped in the polymer (Gombotz andPettit, Bioconjugate Chem. 6:332 (1995); Ranade, “Role of Polymers inDrug Delivery,” in Drug Delivery Systems, Ranade and Hollinger (eds.),pages 51-93 (CRC Press 1995); Roskos and Maskiewicz, “DegradableControlled Release Systems Useful for Protein Delivery,” in ProteinDelivery: Physical Systems, Sanders and Hendren (eds.), pages 45-92(Plenum Press 1997); Bartus et al., Science 281:1161 (1998); Putney andBurke, Nature Biotechnology 16:153 (1998); Putney, Curr. Opin. Chem.Biol. 2:548 (1998)). Polyethylene glycol (PEG)-coated nanospheres canalso provide carriers for intravenous administration of therapeuticproteins (see, for example, Gref et al., Pharm. Biotechnol. 10:167(1997)).

The present invention also contemplates chemically modified polypeptideshaving IL-17A and/or IL-17F binding activity such as IL-17RC orIL-17RC/IL-17RA monomeric, homodimeric, heterodimeric or multimericsoluble receptors, which a polypeptide is linked with a polymer, asdiscussed above.

Other dosage forms can be devised by those skilled in the art, as shown,for example, by Ansel and Popovich, Pharmaceutical Dosage Forms and DrugDelivery Systems, 5^(th) Edition (Lea & Febiger 1990), Gennaro (ed.),Remington's Pharmaceutical Sciences, 19^(th) Edition (Mack PublishingCompany 1995), and by Ranade and Hollinger, Drug Delivery Systems (CRCPress 1996).

As an illustration, pharmaceutical compositions may be supplied as a kitcomprising a container that comprises one of the soluble polypeptides ofthe present invention. Therapeutic polypeptides can be provided in theform of an injectable solution for single or multiple doses, or as asterile powder that will be reconstituted before injection.Alternatively, such a kit can include a dry-powder disperser, liquidaerosol generator, or nebulizer for administration of a therapeuticpolypeptide. Such a kit may further comprise written information onindications and usage of the pharmaceutical composition. Moreover, suchinformation may include a statement that the composition iscontraindicated in patients with known hypersensitivity to IL-17RC orIL-17RA.

A pharmaceutical composition comprising soluble polypeptides of thepresent invention can be furnished in liquid form, in an aerosol, or insolid form. Liquid forms, are illustrated by injectable solutions,aerosols, droplets, topological solutions and oral suspensions.Exemplary solid forms include capsules, tablets, and controlled-releaseforms. The latter form is illustrated by miniosmotic pumps and implants(Bremer et al., Pharm. Biotechnol. 10:239 (1997); Ranade, “Implants inDrug Delivery,” in Drug Delivery Systems, Ranade and Hollinger (eds.),pages 95-123 (CRC Press 1995); Bremer et al., “Protein Delivery withInfusion Pumps,” in Protein Delivery: Physical Systems, Sanders andHendren (eds.), pages 239-254 (Plenum Press 1997); Yewey et al.,“Delivery of Proteins from a Controlled Release Injectable Implant,” inProtein Delivery: Physical Systems, Sanders and Hendren (eds.), pages93-117 (Plenum Press 1997)). Other solid forms include creams, pastes,other topological applications, and the like.

Liposomes provide one means to deliver therapeutic polypeptides to asubject intravenously, intraperitoneally, intrathecally,intramuscularly, subcutaneously, or via oral administration, inhalation,or intranasal administration. Liposomes are microscopic vesicles thatconsist of one or more lipid bilayers surrounding aqueous compartments(see, generally, Bakker-Woudenberg et al., Eur. J. Clin. Microbiol.Infect. Dis. 12 (Suppl. 1):561 (1993), Kim, Drugs 46:618 (1993), andRanade, “Site-Specific Drug Delivery Using Liposomes as Carriers,” inDrug Delivery Systems, Ranade and Hollinger (eds.), pages 3-24 (CRCPress 1995)). Liposomes are similar in composition to cellular membranesand as a result, liposomes can be administered safely and arebiodegradable. Depending on the method of preparation, liposomes may beunilamellar or multilamellar, and liposomes can vary in size withdiameters ranging from 0.02 μm to greater than 10 μm. A variety ofagents can be encapsulated in liposomes: hydrophobic agents partition inthe bilayers and hydrophilic agents partition within the inner aqueousspace(s) (see, for example, Machy et al., Liposomes In Cell Biology AndPharmacology (John Libbey 1987), and Ostro et al., American J. Hosp.Pharm. 46:1576 (1989)). Moreover, it is possible to control thetherapeutic availability of the encapsulated agent by varying liposomesize, the number of bilayers, lipid composition, as well as the chargeand surface characteristics of the liposomes.

Liposomes can adsorb to virtually any type of cell and then slowlyrelease the encapsulated agent. Alternatively, an absorbed liposome maybe endocytosed by cells that are phagocytic. Endocytosis is followed byintralysosomal degradation of liposomal lipids and release of theencapsulated agents (Scherphof et al., Ann. N.Y. Acad. Sci. 446:368(1985)). After intravenous administration, small liposomes (0.1 to 1.0μm) are typically taken up by cells of the reticuloendothelial system,located principally in the liver and spleen, whereas liposomes largerthan 3.0 μm are deposited in the lung. This preferential uptake ofsmaller liposomes by the cells of the reticuloendothelial system hasbeen used to deliver chemotherapeutic agents to macrophages and totumors of the liver.

The reticuloendothelial system can be circumvented by several methodsincluding saturation with large doses of liposome particles, orselective macrophage inactivation by pharmacological means (Claassen etal., Biochim. Biophys. Acta 802:428 (1984)). In addition, incorporationof glycolipid- or polyethelene glycol-derivatized phospholipids intoliposome membranes has been shown to result in a significantly reduceduptake by the reticuloendothelial system (Allen et al., Biochim.Biophys. Acta 1068:133 (1991); Allen et al., Biochim. Biophys. Acta1150:9 (1993)).

Liposomes can also be prepared to target particular cells or organs byvarying phospholipid composition or by inserting receptors or ligandsinto the liposomes. For example, liposomes, prepared with a high contentof a nonionic surfactant, have been used to target the liver (Hayakawaet al., Japanese Patent 04-244,018; Kato et al., Biol. Pharm. Bull.16:960 (1993)). These formulations were prepared by mixing soybeanphospatidylcholine, α-tocopherol, and ethoxylated hydrogenated castoroil (HCO-60) in methanol, concentrating the mixture under vacuum, andthen reconstituting the mixture with water. A liposomal formulation ofdipalmitoylphosphatidylcholine (DPPC) with a soybean-derivedsterylglucoside mixture (SG) and cholesterol (Ch) has also been shown totarget the liver (Shimizu et al., Biol. Pharm. Bull. 20:881 (1997)).

Alternatively, various targeting ligands can be bound to the surface ofthe liposome, such as antibodies, antibody fragments, carbohydrates,vitamins, and transport proteins. For example, liposomes can be modifiedwith branched type galactosyllipid derivatives to targetasialoglycoprotein (galactose) receptors, which are exclusivelyexpressed on the surface of liver cells (Kato and Sugiyama, Crit. Rev.Ther. Drug Carrier Syst. 14:287 (1997); Murahashi et al., Biol. Pharm.Bull. 20:259 (1997)). Similarly, Wu et al., Hepatology 27:772 (1998),have shown that labeling liposomes with asialofetuin led to a shortenedliposome plasma half-life and greatly enhanced uptake ofasialofetuin-labeled liposome by hepatocytes. On the other hand, hepaticaccumulation of liposomes comprising branched type galactosyllipidderivatives can be inhibited by preinjection of asialofetuin (Murahashiet al., Biol. Pharm. Bull. 20:259 (1997)). Polyaconitylated human serumalbumin liposomes provide another approach for targeting liposomes toliver cells (Kamps et al., Proc. Nat'l Acad. Sci. USA 94:11681 (1997)).Moreover, Geho, et al. U.S. Pat. No. 4,603,044, describe ahepatocyte-directed liposome vesicle delivery system, which hasspecificity for hepatobiliary receptors associated with the specializedmetabolic cells of the liver.

In a more general approach to tissue targeting, target cells areprelabeled with biotinylated antibodies specific for a ligand expressedby the target cell (Harasym et al., Adv. Drug Deliv. Rev. 32:99 (1998)).After plasma elimination of free antibody, streptavidin-conjugatedliposomes are administered. In another approach, targeting antibodiesare directly attached to liposomes (Harasym et al., Adv. Drug Deliv.Rev. 32:99 (1998)).

The soluble polypeptides of the present invention can be encapsulatedwithin liposomes using standard techniques of protein microencapsulation(see, for example, Anderson et al., Infect. Immun. 31:1099 (1981),Anderson et al., Cancer Res. 50:1853 (1990), and Cohen et al., Biochim.Biophys. Acta 1063:95 (1991), Alving et al. “Preparation and Use ofLiposomes in Immunological Studies,” in Liposome Technology, 2ndEdition, Vol. III, Gregoriadis (ed.), page 317 (CRC Press 1993), Wassefet al., Meth. Enzymol. 149:124 (1987)). As noted above, therapeuticallyuseful liposomes may contain a variety of components. For example,liposomes may comprise lipid derivatives of poly(ethylene glycol) (Allenet al., Biochim. Biophys. Acta 1150:9 (1993)).

Degradable polymer microspheres have been designed to maintain highsystemic levels of therapeutic proteins. Microspheres are prepared fromdegradable polymers such as poly(lactide-co-glycolide) (PLG),polyanhydrides, poly (ortho esters), nonbiodegradable ethylvinyl acetatepolymers, in which proteins are entrapped in the polymer (Gombotz andPettit, Bioconjugate Chem. 6:332 (1995); Ranade, “Role of Polymers inDrug Delivery,” in Drug Delivery Systems, Ranade and Hollinger (eds.),pages 51-93 (CRC Press 1995); Roskos and Maskiewicz, “DegradableControlled Release Systems Useful for Protein Delivery,” in ProteinDelivery: Physical Systems, Sanders and Hendren (eds.), pages 45-92(Plenum Press 1997); Bartus et al., Science 281:1161 (1998); Putney andBurke, Nature Biotechnology 16:153 (1998); Putney, Curr. Opin. Chem.Biol. 2:548 (1998)). Polyethylene glycol (PEG)-coated nanospheres canalso provide carriers for intravenous administration of therapeuticproteins (see, for example, Gref et al., Pharm. Biotechnol. 10:167(1997)).

Other dosage forms can be devised by those skilled in the art, as shown,for example, by Ansel and Popovich, Pharmaceutical Dosage Forms and DrugDelivery Systems, 5^(th) Edition (Lea & Febiger 1990), Gennaro (ed.),Remington's Pharmaceutical Sciences, 19^(th) Edition (Mack PublishingCompany 1995), and by Ranade and Hollinger, Drug Delivery Systems (CRCPress 1996).

The present invention contemplates compositions of the solublepolypeptides of the present invention, and methods and therapeutic usescomprising the same polypeptide described herein. Such compositions canfurther comprise a carrier. The carrier can be a conventional organic orinorganic carrier. Examples of carriers include water, buffer solution,alcohol, propylene glycol, macrogol, sesame oil, corn oil, and the like.

K) Production of Transgenic Mice

Transgenic mice can be engineered to over-express the either IL-17F,IL-17A, IL-17RA or the IL-17RC gene in all tissues or under the controlof a tissue-specific or tissue-preferred regulatory element. Theseover-producers can be used to characterize the phenotype that resultsfrom over-expression, and the transgenic animals can serve as models forhuman disease caused by excess IL-17F, IL-17A, IL-17RA or IL-17RC.Transgenic mice that over-express any of these also provide modelbioreactors for production of IL-17RA or IL-17RC, such as any of thesoluble polypeptides of the present invention in milk or blood of largeranimals. Methods for producing transgenic mice are well-known to thoseof skill in the art (see, for example, Jacob, “Expression and Knockoutof Interferons in Transgenic Mice,” in Overexpression and Knockout ofCytokines in Transgenic Mice, Jacob (ed.), pages 111-124 (AcademicPress, Ltd. 1994), Monastersky and Robl (eds.), Strategies in TransgenicAnimal Science (ASM Press 1995), and Abbud and Nilson, “RecombinantProtein Expression in Transgenic Mice,” in Gene Expression Systems:Using Nature for the Art of Expression, Fernandez and Hoeffler (eds.),pages 367-397 (Academic Press, Inc. 1999)).

For example, a method for producing a transgenic mouse that expresses aIL-17RC gene can begin with adult, fertile males (studs) (B6C3f1, 2-8months of age (Taconic Farms, Germantown, N.Y.)), vasectomized males(duds) (B6D2f1, 2-8 months, (Taconic Farms)), prepubescent fertilefemales (donors) (B6C3f1, 4-5 weeks, (Taconic Farms)) and adult fertilefemales (recipients) (B6D2f1, 2-4 months, (Taconic Farms)). The donorsare acclimated for one week and then injected with approximately 8IU/mouse of Pregnant Mare's Serum gonadotrophin (Sigma Chemical Company;St. Louis, Mo.) I.P., and 46-47 hours later, 8 IU/mouse of humanChorionic Gonadotropin (hCG (Sigma)) I.P. to induce superovulation.Donors are mated with studs subsequent to hormone injections. Ovulationgenerally occurs within 13 hours of hCG injection. Copulation isconfirmed by the presence of a vaginal plug the morning followingmating.

Fertilized eggs are collected under a surgical scope. The oviducts arecollected and eggs are released into urinanalysis slides containinghyaluronidase (Sigma). Eggs are washed once in hyaluronidase, and twicein Whitten's W640 medium (described, for example, by Menino andO'Claray, Biol. Reprod. 77:159 (1986), and Dienhart and Downs, Zygote4:129 (1996)) that has been incubated with 5% CO₂, 5% O2, and 90% N₂ at37° C. The eggs are then stored in a 37° C./5% CO₂ incubator untilmicroinjection.

Ten to twenty micrograms of plasmid DNA containing a IL-17RC encodingsequence is linearized, gel-purified, and resuspended in 10 mM Tris-HCl(pH 7.4), 0.25 mM EDTA (pH 8.0), at a final concentration of 5-10nanograms per microliter for microinjection. For example, the IL-17RCencoding sequences can encode a polypeptide comprising amino acidresidues 21 to 452 of SEQ ID NO:2.

Plasmid DNA is microinjected into harvested eggs contained in a drop ofW640 medium overlaid by warm, CO2-equilibrated mineral oil. The DNA isdrawn into an injection needle (pulled from a 0.75 mm ID, 1 mm ODborosilicate glass capillary), and injected into individual eggs. Eachegg is penetrated with the injection needle, into one or both of thehaploid pronuclei.

Picoliters of DNA are injected into the pronuclei, and the injectionneedle withdrawn without coming into contact with the nucleoli. Theprocedure is repeated until all the eggs are injected. Successfullymicroinjected eggs are transferred into an organ tissue-culture dishwith pre-gassed W640 medium for storage overnight in a 37° C./5% CO₂incubator.

The following day, two-cell embryos are transferred into pseudopregnantrecipients. The recipients are identified by the presence of copulationplugs, after copulating with vasectomized duds. Recipients areanesthetized and shaved on the dorsal left side and transferred to asurgical microscope. A small incision is made in the skin and throughthe muscle wall in the middle of the abdominal area outlined by theribcage, the saddle, and the hind leg, midway between knee and spleen.The reproductive organs are exteriorized onto a small surgical drape.The fat pad is stretched out over the surgical drape, and a babyserrefine (Roboz, Rockville, Md.) is attached to the fat pad and lefthanging over the back of the mouse, preventing the organs from slidingback in.

With a fine transfer pipette containing mineral oil followed byalternating W640 and air bubbles, 12-17 healthy two-cell embryos fromthe previous day's injection are transferred into the recipient. Theswollen ampulla is located and holding the oviduct between the ampullaand the bursa, a nick in the oviduct is made with a 28 g needle close tothe bursa, making sure not to tear the ampulla or the bursa.

The pipette is transferred into the nick in the oviduct, and the embryosare blown in, allowing the first air bubble to escape the pipette. Thefat pad is gently pushed into the peritoneum, and the reproductiveorgans allowed to slide in. The peritoneal wall is closed with onesuture and the skin closed with a wound clip. The mice recuperate on a37° C. slide warmer for a minimum of four hours.

The recipients are returned to cages in pairs, and allowed 19-21 daysgestation. After birth, 19-21 days postpartum is allowed before weaning.The weanlings are sexed and placed into separate sex cages, and a 0.5 cmbiopsy (used for genotyping) is snipped off the tail with cleanscissors.

Genomic DNA is prepared from the tail snips using, for example, a QiagenDneasy kit following the manufacturer's instructions. Genomic DNA isanalyzed by PCR using primers designed to amplify a IL-17RC gene or aselectable marker gene that was introduced in the same plasmid. Afteranimals are confirmed to be transgenic, they are back-crossed into aninbred strain by placing a transgenic female with a wild-type male, or atransgenic male with one or two wild-type female(s). As pups are bornand weaned, the sexes are separated, and their tails snipped forgenotyping.

To check for expression of a transgene in a live animal, a partialhepatectomy is performed. A surgical prep is made of the upper abdomendirectly below the zyphoid process. Using sterile technique, a small1.5-2 cm incision is made below the sternum and the left lateral lobe ofthe liver exteriorized. Using 4-0 silk, a tie is made around the lowerlobe securing it outside the body cavity. An atraumatic clamp is used tohold the tie while a second loop of absorbable Dexon (American Cyanamid;Wayne, N.J.) is placed proximal to the first tie. A distal cut is madefrom the Dexon tie and approximately 100 mg of the excised liver tissueis placed in a sterile petri dish. The excised liver section istransferred to a 14 ml polypropylene round bottom tube and snap frozenin liquid nitrogen and then stored on dry ice. The surgical site isclosed with suture and wound clips, and the animal's cage placed on a37° C. heating pad for 24 hours post operatively. The animal is checkeddaily post operatively and the wound clips removed 7-10 days aftersurgery. The expression level of IL-17RC mRNA is examined for eachtransgenic mouse using an RNA solution hybridization assay or polymerasechain reaction.

In addition to producing transgenic mice that over-express IL-17F,IL-17A, IL-17RA or IL-17RC, it is useful to engineer transgenic micewith either abnormally low or no expression of any of these genes. Suchtransgenic mice provide useful models for diseases associated with alack of IL-17F, IL-17A, IL-17RA or IL-17RC. As discussed above, IL-17RCgene expression can be inhibited using anti-sense genes, ribozyme genes,or external guide sequence genes. For example, to produce transgenicmice that under-express the IL-17RC gene, such inhibitory sequences aretargeted to IL-17RC mRNA. Methods for producing transgenic mice thathave abnormally low expression of a particular gene are known to thosein the art (see, for example, Wu et al., “Gene Underexpression inCultured Cells and Animals by Antisense DNA and RNA Strategies,” inMethods in Gene Biotechnology, pages 205-224 (CRC Press 1997)).

An alternative approach to producing transgenic mice that have little orno IL-17RC gene expression is to generate mice having at least onenormal IL-17RC allele replaced by a nonfunctional IL-17RC gene. Onemethod of designing a nonfunctional IL-17RC gene is to insert anothergene, such as a selectable marker gene, within a nucleic acid moleculethat encodes IL-17RC. Standard methods for producing these so-called“knockout mice” are known to those skilled in the art (see, for example,Jacob, “Expression and Knockout of Interferons in Transgenic Mice,” inOverexpression and Knockout of Cytokines in Transgenic Mice, Jacob(ed.), pages 111-124 (Academic Press, Ltd. 1994), and Wu et al., “NewStrategies for Gene Knockout,” in Methods in Gene Biotechnology, pages339-365 (CRC Press 1997)).

The invention is further illustrated by the following non-limitingexamples.

Example 1 Expression of the IL-17RC Gene

Northern analyses were performed using Human Multiple Tissue Blots(Clontech Laboratories, Inc., Palo Alto, Calif.). Two probes weregenerated from gel purified PCR products. The first probe was made usingZC21798 (5′ CGG CGT GGT GGT CTT GCT CTT 3′; SEQ ID NO:8) and ZC21808 (5′TCC CGT CCC CCG CCC CAG GTC 3′; SEQ ID NO:31) as primers. The probe wasa radioactively labeled using the Multiprime labeling kit from Amersham(Arlington Heights, Ill.) according to the manufacturer's protocol. Theprobe was purified using a NucTrap push column (Stratagene, La Jolla,Calif.). ExpressHyb (Clontech) solution was used for theprehybridization and hybridization solutions for the northern blots.Hybridization took place overnight at 65° C. Following hybridization,the blots were washed for 30 minutes each in solutions that contained0.1% SDS and SSC as follows: twice in 2×SSC at room temperature, threetimes in 0.1×SSC at 50° C., once in 0.1×SSC at 55° C., and once in0.1×SSC at 65° C. The results demonstrated the IL-17RC gene is stronglyexpressed in thyroid, adrenal gland, prostate, and liver tissues, andexpressed to a lesser extent in heart, small intestine, stomach, andtrachea tissues. In contrast, there is little or no expression in brain,placenta, lung, skeletal muscle, kidney, pancreas, spleen, thymus,testis, ovary, colon, peripheral blood leukocytes, spinal cord, lymphnode, and bone marrow.

Example 2 Distribution of mRNA in Cell Line Panels Using PCR

Total RNA was purified from resting and stimulated cell lines grownin-house and purified using a Qiagen (Valencia, Calif.) RNeasy kitaccording to the manufacturer's instructions, or an acid-phenolpurification protocol (Chomczynski and Sacchi, Analytical Biochemistry,162:156-9, 1987). The quality of the RNA was assessed by running analiquot on an Agilent Bioanalyzer. If the RNA was significantlydegraded, it was not used for subsequent creation of first strand cDNA.Presence of contaminating genomic DNA was assessed by a PCR assay on analiquot of the RNA with zc41011 (5′CTCTCCATCCTTATCTTTCATCAAC 3′; SEQ IDNO:32) and zc41012 (5′CTCTCTGCTGGCTAAACAAAACAC 3′; SEQ ID NO:33),primers that amplify a single site of intergenic genomic DNA. The PCRconditions for the contaminating genomic DNA assay were as follows: 2.5μl 10× buffer and 0.5 μl Advantage 2 cDNA polymerase mix (BD BiosciencesClontech, Palo Alto, Calif.), 2 ul 2.5 mM dNTP mix (Applied Biosystems,Foster City, Calif.), 2.5 μl 10× Rediload (Invitrogen, Carlsbad,Calif.), and 0.5 μl 20 uM zc41011 and zc41012, in a final volume of 25ul. Cycling parameters were 94° C. 20″, 40 cycles of 94° C. 20″ 60° C.1′20″ and one cycle of 72° C. 7′. 10 μl of each reaction was subjectedto agarose gel electrophoresis and gels were examined for presence of aPCR product from contaminating genomic DNA. If contaminating genomic DNAwas observed, the total RNA was DNAsed using DNA-free reagents (Ambion,Inc, Austin, Tex.) according to the manufacturer's instructions, thenretested as described above. Only RNAs which appeared to be free ofcontaminating genomic DNA were used for subsequent creation of firststrand cDNA.

20 μl total RNA from 82 human cell lines were each brought to 98 μl withH2O, then split into two 49 ul aliquots, each containing 10 μg totalRNA, and placed in two 96-well PCR plates. To each aliquot was addedreagents for first strand cDNA synthesis (Invitrogen First Strand cDNASynthesis System, Carlsbad, Calif.): 20 μl 25 mM MgCl₂, 10 ul 10× RTbuffer, 10 ul 0.1M DTT, 2 μl oligo dT, 2 μl RNAseOut. Then, to onealiquot from each cell line 2 μl Superscript II Reverse Transcriptasewas added, and to the corresponding cell line aliquot 2 μl H₂O was addedto make a minus Reverse Transcriptase negative control. All samples wereincubated as follows: 25° C. 10′, 42° C. 50′, 70° C. 15′. Samples werearranged in deep well plates and diluted to 1.7 ml with H₂O. AMultipette (Saigan) robot was used to aliquot 16.5 μl into each well ofa 96-well PCR plate multiple times, generating numerous one-use PCRpanels of the cell lines, which were then sealed and stored at −20° C.Each well in these panels represents first strand cDNA fromapproximately 100 ng total RNA. The 82 cell lines are spread across twopanels, array #118A and #118B. Quality of first strand cDNA on thepanels was assessed by a multiplex PCR assay on one set of the panelsusing primers to two widely expressed, but only moderately abundantgenes, CLTC (clathrin) and TFRC (transferrin receptor C). 0.5 μl each ofClathrin primers zc42901 (5′CTCATATTGCTCAACTGTGTGAAAAG 3′; SEQ IDNO:34), zc42902(5′TAGAAGCCACCTGAACACAAATCTG3′; SEQ ID NO:35), and TFRCprimers zc42599 (5′ ATCTTGCGTTGTATGTTGAAAATCAATT3′; SEQ ID NO:36),zc42600 (5′TTCTCCACCAGGTAAACAAGTCTAC3′; SEQ ID NO:37), were mixed with2.5 μl 10× buffer and 0.5 μl Advantage 2 cDNA polymerase mix (BDBiosciences Clontech, Palo Alto, Calif.), 2 μl 2.5 mM dNTP mix (AppliedBiosystems, Foster City, Calif.), 2.5 μl 10× Rediload (Invitrogen,Carlsbad, Calif.), and added to each well of a panel of array#118A andarray #118B. Cycling parameters were as follows: 94° C. 20″, 35 cyclesof 94° C. 20″, 67° C. 80″, and one cycle of 72° C. 7′. 10 μl of eachreaction was subjected to agarose gel electrophoresis and gels werescored for the presence of a robust PCR product for each gene specificto the +RT wells for each cell line.

Expression of mRNA in the human first strand cDNA panels for IL-17RC wasassayed by PCR with sense oligo ZC42756 (5′ ctctccaggcccaagtcgtgctct3′;SEQ ID NO:38) and antisense oligo ZC42757 (5′ttgtcctgggggcctcgtgtctcc3′; SEQ ID NO:39) under these PCR conditions persample: 2.5 μl 10× buffer and 0.5 μl advantage 2 cDNA polymerase mix (BDBiosciences Clontech, Palo Alto, Calif.), 2 μl 2.5 mM dNTP mix (AppliedBiosystems), 2.5 ul 10× Rediload (Invitrogen, Carlsbad, Calif.), and 0.5μl 20 uM each sense and antisense primer. Cycling conditions were 94° C.2′, 35 cycles of 94° C. 1′, 66° C. 30″, 72° C. 1.5°, and one cycle of72° C. 7′. 10 μl of each reaction was subjected to agarose gelelectrophoresis and gels were scored for positive or negative expressionof IL-17RC.

IL-17RC mRNA is widely expressed in many cell lines representing a broadspectrum of tissue and cell types. In particular, IL-17RC isconsistently expressed in non-T cell peripheral blood cell lines,including monocytes, B-cells, and cells of the myeloid lineage. Also,IL-17RC mRNA is reliably expressed in cell lines derived from skin.Other cell lines that express IL-17RC are all 5 of the large intestinecell lines that were present on the array.

Example 3 Distribution of mRNA in Mouse Cell Line Panels Using RT PCR

Total RNA was purified from 60 resting and stimulated cell lines grownin-house and purified using a Qiagen (Valencia, Calif.) RNeasy kitaccording to the manufacturer's instructions, an acid-phenolpurification protocol (Chomczynski and Sacchi, Analytical Biochemistry,162:156-9, 1987), or a Trizol reagent protocol (Invitrogen, Carlsbad,Calif.).

5 μg of total RNA from each cell line was arranged in a deep well96-well plate, 125 μl M NaOAc and 100 μl Pellet Paint (Novagen, Madison,Wis.)) were added to each well, then the final volume was adjusted to1.25 ml with H₂O. A Multipette (Saigan) robot was used to aliquot 25 μlof the RNA mixture followed by 75 ul EtOH into each well of a 96-wellPCR plate multiple times, generating numerous one-use RT PCR panels ofthe cell lines, which were then sealed and stored at −20° C. RT PCRscreening was performed by first centrifuging a panel in a Qiagen(Valencia, Calif.) 96-well centrifuge for 10′ at 6000 RPM. Supernatantwas removed by inverting the plate onto absorbent paper. RNA pelletswere washed with 100 μl 70% EtOH, followed by a 5′ centrifugation at6000 RPM. Supernatant was again removed and plates allowed to air-dryuntil the remaining EtOH was evaporated. RNA pellets were resuspended in15 μl H20.

Expression of IL-17RC mRNA in the mouse cell line RNA panels was assayedby RT PCR with zc38910 (5′ acgaagcccaggtaccagaaagag3′; SEQ ID NO:40) andzc38679 (5′ aaaagcgccgcagccaagagtagg3′; SEQ ID NO:41) under these RT PCRconditions per sample: SuperScript One-Step PCR with Platinum Taq kit,Invitrogen, Carlsbad, Calif. Cycling conditions were: 1 cycle of 48° C.for 30 minutes, 94° C. for 2 minutes, followed by 35 cycles of 94° C.for 15 seconds, 55° C. for 30 seconds, 72° C. for 1.5 minutes, followedby 1 cycle of 72° C. for 7 minutes. 10 μl of each reaction was subjectedto agarose gel electrophoresis and gels were scored for positive ornegative expression of IL-17RC.

Murine IL-17RCmRNA is expressed in several mouse cell lines, notably incell lines derived from bone marrow, including osteoblast, adipocyte,and preadipocyte cell lines. Also, mouse IL-17RC is mRNA is representedin several samples from the endocrine system, such as pancreas stromalcell lines, pancreas islet cell lines, and hypothalamus, salivary gland,and testis cell lines.

Example 4 Refolding and Purification pIL-17F Produced in E. coli

A) Inclusion body isolation and extraction of pIL-17F

Following induction of protein expression in either batch ferment orshaker flask culture, the E. coli broth is centrifuged in 1 literbottles @ 3000 RPM in a Sorvall swinging bucket rotor. Washing of thecell paste to remove any broth contaminants is performed with 50 mM TrispH 8.0 containing 200 mM NaCl and 5 mM EDTA until the supernate isclear.

The cell pellets are then suspended in ice-cold lysis buffer (50 mM TrispH 8.0; 5 mM EDTA; 200 mM NaCl, 10% sucrose (w/v); 5 mM DTT; 5 mMBenzamidine) to 10-20 Optical Density units at 600 nm. This slurry isthen subjected to 3 passes at 8500-9000 psi in a chilled APV 2000 LabHomogenizer producing a disrupted cell lysate. The insoluble fraction(inclusion bodies) is recovered by centrifugation of the cell lysate at20,000×G for 1 hour at 4° C.

The inclusion body pellet resulting from the 20,000×G spin is weighedand then re-suspended in wash buffer (50 mM Tris pH 8 containing 200 mMNaCl, 5 mM EDTA, 5 mM DTT, 5 mM Benzamidine) at 10 ml wash buffer pergram inclusion bodies. Complete dispersion is achieved by homogenizingwith an OMNI international rotor stator generator. This suspension iscentrifuged at 20,000×G for 30 minutes at 4° C. The wash cycle isrepeated 3-5 times until the supernatant is clear.

The final washed pellet is solubilized in 7M Guanidine HCl in 40 mM Trisbuffer at pH 8 containing 0.1M Sodium Sulfite and 0.02 M SodiumTetrathionate. The extraction and sulfitolysis reaction is allowed toproceed with gentle stirring at 4° C. overnight. The resulting pinkishcolored solution is centrifuged at 35,000×g for 1 hour at 4° C. and theclarified supernate, containing the soluble pIL-17F, is 0.45 μmfiltered.

B) pIL-17F Refolding Procedure

The solubilized, sulfitolyzed pIL-17F is refolded by drop wise dilutioninto ice cold refolding buffer containing 55 mM MES, 10.56 mM NaCl, 0.44mM KCl, 0.055% PEG (3400 K), 1.1 mM EDTA, 20% Glycerol, 0.5M GuanidineHCl, 0.75 M Arginine and the Glutathione redox pair at a 1:1 ratio (1 mMGSH:1 mM GSSG). The pH of the refolding buffer is adjusted to 6.5 withHCl and the pIL-17F is added to a final concentration of 100 ug/ml. Oncediluted, the mixture is allowed to stir slowly in the cold room for 72hours.

C) Product Recovery & Purification

The refolded pIL-17F is concentrated 10×vs. a 10 kDa cutoff membrane ona lab scale TFF system. Next it is filtered using a 0.45 micron membraneand the pH is adjusted to 5.1 with the addition of Acetic acid. ThepH-adjusted material is captured by cation exchange chromatography on aPharmacia SP Fast Flow column equilibrated in 50 mM Acetate buffer, pH5.1. The pIL-17F is loaded by inline proportioning at 1:5 withequilibration buffer at a flow rate of 190 cm/hr. This dilution lowersthe ionic strength enabling efficient binding of the target to thematrix. After sample loading is complete, the column is washed tobaseline absorbance with equilibration buffer. The column is washed with0.4 M NaCl in 50 mM Acetate buffer at pH 5.1 and then the bound proteinis eluted with a 5 CV gradient from 0.4 M to 1.5 M NaCl in 50 mM Acetatebuffer at pH 5.1. The protein elutes at ˜1M NaCl and is approximately85% dimeric by SDS PAGE analysis of eluate fractions. The fractionscontaining pIL-17F are pooled and concentrated against a 10 kDa cutoffultrafiltration membrane using an Amicon stirred cell in preparation forthe final purification and buffer exchange by size exclusionchromatography.

D) Size Exclusion Buffer Exchange and Formulation

The concentrated cation pool (at a volume of 3-4% of CV) is injected ata flow rate of 30 cm/hr onto a Pharmacia Superdex 75 size exclusioncolumn equilibrated in 50 mM Sodium Phosphate buffer containing 109 mMNaCl, pH 7.2. The symmetric eluate peak containing the product isdiluted to a concentration of 1 mg/ml in 50 mM Sodium Phosphate buffercontaining 109 mM NaCl, pH 7.2. Finally the pIL-17F is 0.2 micronsterile filtered, aliquoted and stored at −80° C. The final processyield is 20%.

Example 5 Construction of Mammalian Soluble IL-17RC Expression Construct

An expression construct containing human IL-17RC [L21-K451]-mFc1 (mouseBALB/c μ2a Fc) is constructed via overlap PCR and homologousrecombination using a DNA fragment (SEQ ID NO:42) encoding a IL-17RCpolypeptide (SEQ ID NO:43), a DNA fragment encoding mFc1 (SEQ ID NO:44),and the expression vector pZMP20. The fragments are generated by PCRamplification.

The PCR fragment encoding IL-17RC [L21-K451] contains a 5′ overlap withthe pZMP20 vector sequence in the optimized tissue plasminogen activatorpre-pro secretion leader sequence coding region, the IL-17RCextracellular domain coding [L21-K451], and a 3′ overlap with the mFc1coding region. The PCR amplification reaction uses the 5′oligonucleotide [GTTTCGCTCAGCCAGGAAATCCATGCCGAGTTGAGACGCTTCCGTAGACTGGAGAGGCTTGTGGGGCCT; SEQ ID NO:46], the 3′ oligonucleotide[TGTGGGCCCTCTGGGCTCCTTGTGGATGTATTTGTC; SEQ ID NO:47], and a previouslygenerated DNA clone of IL-17RC as the template.

The PCR fragment encoding mFc1 contains a 5′ overlap with the IL-17RCsequence, the mFc1 coding region, and a 3′ overlap with the pZMP20vector in the poliovirus internal ribosome entry site region. The PCRamplification reaction uses the 5 oligonucleotide[GACAAATACATCCACAAGGAGCCCAGAGGGCCCACA; SEQ ID NO:48], the 3′oligonucleotide [CAACCCCAGAGCTGTTTTAAGGCGCGCCTCTAGATTATTTACCCGGAGTCCGGGA; SEQ ID NO:49], and a previously generated DNA clone of mFc1 as thetemplate.

The PCR amplification reaction conditions are as follows: 1 cycle, 94°C., 5 minutes; 35 cycles, 94° C., 1 minute, followed by 55° C., 2minutes, followed by 72° C., 3 minutes; 1 cycle, 72° C., 10 minutes. ThePCR reaction mixtures are run on a 1% agarose gel and the DNA fragmentscorresponding to the expected sizes are extracted from the gel using aQIAquick™ Gel Extraction Kit (Qiagen, Cat. No. 28704).

The two PCR fragments are joined by overlap PCR. Approximately 1 μl eachof the two gel extracted fragments are combined in a PCR amplificationreaction using the 5′ oligonucleotide[GTTTCGCTCAGCCAGGAAATCCATGCCGAGTTGAGACGCTTCCGTAGACTGGAG AGGCTTGTGGGGCCT;SEQ ID NO: 46] and the 3′ oligonucleotide[CAACCCCAGAGCTGTTTTAAGGCGCGCCTCTAGATTATTTACCCGGAGTCCGGG A; SEQ IDNO:49]. PCR conditions used are as follows: 1 cycle, 94° C., 5 minutes;35 cycles, 94° C., 1 minute, followed by 55° C., 2 minutes, followed by72° C., 3 minutes; 1 cycle, 72° C., 10 minutes. The PCR reaction mixtureis run on a 1% agarose gel and the DNA fragment corresponding to thesize of the insert is extracted from the gel using a QIAquick™ GelExtraction Kit (Qiagen, Cat. No. 28704).

Plasmid pZMP20 is a mammalian expression vector containing an expressioncassette having the MPSV promoter, a BgIII site for linearization priorto yeast recombination, an otPA signal peptide sequence, an internalribosome entry element from poliovirus, the extracellular domain of CD8truncated at the C-terminal end of the transmembrane domain; an E. coliorigin of replication; a mammalian selectable marker expression unitcomprising an SV40 promoter, enhancer and origin of replication, a DHFRgene, and the SV40 terminator; and URA3 and CEN-ARS sequences requiredfor selection and replication in S. cerevisiae.

The plasmid pZMP20 is digested with BgIII prior to recombination inyeast with the gel extracted IL-17RC[L21-K451]-mFc1 PCR fragment. 100 μlof competent yeast (S. cerevisiae) cells are combined with 10 μl of theIL-17RC[L21-K451]-mFc1 insert DNA and 100 ng of BgIII digested pZMP20vector, and the mix is transferred to a 0.2 cm electroporation cuvette.The yeast/DNA mixture is electropulsed using power supply (BioRadLaboratories, Hercules, Calif.) settings of 0.75 kV (5 kV/cm), ∞ ohms,and 25 μf. Six hundred μl of 1.2 M sorbitol is added to the cuvette, andthe yeast is plated in 100 μl and 300 μl aliquots onto two URA-D platesand incubated at 30° C. After about 72 hours, the Ura+ yeasttransformants from a single plate are resuspended in 1 ml H₂O and spunbriefly to pellet the yeast cells. The cell pellet is resuspended in 0.5ml of lysis buffer (2% Triton X-100, 1% SDS, 100 mM NaCl, 10 mM Tris, pH8.0, 1 mM EDTA). The five hundred μl of the lysis mixture is added to anEppendorf tube containing 250 μl acid-washed glass beads and 300 μlphenol-chloroform, is vortexed for 3 minutes, and spun for 5 minutes inan Eppendorf centrifuge at maximum speed. Three hundred μl of theaqueous phase is transferred to a fresh tube, and the DNA isprecipitated with 600 μl ethanol, followed by centrifugation for 30minutes at maximum speed. The tube is decanted and the pellet is washedwith 1 mL of 70% ethanol. The tube is decanted and the DNA pellet isresuspended in 30 μl 10 mM Tris, pH 8.0, 1 mM EDTA.

Transformation of electrocompetent E. coli host cells (DH12S) is doneusing 5 μl of the yeast DNA preparation and 50 μl of E. coli cells. Thecells are electropulsed at 2.0 kV, 25 μF, and 400 ohms. Followingelectroporation, 1 ml SOC (2% Bacto™ Tryptone (Difco, Detroit, Mich.),0.5% yeast extract (Difco), 10 mM NaCl, 2.5 mM KCl, 10 mM MgCl₂, 10 mMMgSO₄, 20 mM glucose) is added and then the cells are plated in 50 μland 200 μl aliquots on two LB AMP plates (LB broth (Lennox), 1.8% Bacto™Agar (Difco), 100 mg/L Ampicillin).

The inserts of three DNA clones for the construct is subjected tosequence analysis and one clone containing the correct sequence isselected. Large scale plasmid DNA is isolated using a commerciallyavailable kit (QIAGEN Plasmid Mega Kit, Qiagen, Valencia, Calif.)according to manufacturer's instructions.

Example 6

Construction of Mammalian Soluble IL-17RC Expression Constructs thatExpress IL-17RC-CEE, IL-17RC-CHIS, and IL-17RC-CFLAG

An expression construct containing human IL-17RC [L21-K451] with aC-terminal tag, either Glu-Glu (CEE), six His (CHIS), or FLAG (CFLAG),is constructed via PCR and homologous recombination using a DNA fragmentencoding IL-17RC [L21-K451] (SEQ ID NO:42) and the expression vectorpZMP20.

The PCR fragment encoding IL-17RCCEE contains a 5′ overlap with thepZMP20 vector sequence in the optimized tissue plasminogen activatorpre-pro secretion leader sequence coding region, the IL-17RCextracellular domain coding [L21-K451], the sequence of the Glu-Glu tag(Glu Glu Tyr Met Pro Met Glu; SEQ ID NO:53), and a 3′ overlap with thepZMP20 vector in the poliovirus internal ribosome entry site region. ThePCR amplification reaction uses the 5′ oligonucleotide[GTTTCGCTCAGCCAGGAAATCCATGCCGAGTTGAGACGCTTCCGTAGACTGGAG AGGCTTGTGGGGCCT;SEQ ID NO:46], the 3′ oligonucleotide[CAACCCCAGAGCTGTTTTAAGGCGCGCCTCTAGATTATTCCATGGGCATGTATTCTTCCTTGTGGATGTATTTGTC; SEQ ID NO:50], and a previously generated DNAclone of IL-17RC as the template.

The PCR amplification reaction condition is as follows: 1 cycle, 94° C.,5 minutes; 35 cycles, 94° C., 1 minute, followed by 55° C., 2 minutes,followed by 72° C., 3 minutes; 1 cycle, 72° C., 10 minutes. The PCRreaction mixture is run on a 1% agarose gel and the DNA fragmentcorresponding to the expected size is extracted from the gel using aQIAquick™ Gel Extraction Kit (Qiagen, Cat. No. 28704).

The plasmid pZMP20 is digested with BgIII prior to recombination inyeast with the gel extracted IL-17RCCEE PCR fragment. One hundred μl ofcompetent yeast (S. cerevisiae) cells are combined with 10 μl of theIL-17RCCEE insert DNA and 100 ng of BgIII digested pZMP20 vector, andthe mix is transferred to a 0.2 cm electroporation cuvette. Theyeast/DNA mixture is electropulsed using power supply (BioRadLaboratories, Hercules, Calif.) settings of 0.75 kV (5 kV/cm), ∞ ohms,and 25 μf. Six hundred μl of 1.2 M sorbitol is added to the cuvette, andthe yeast is plated in 100 μl and 300 μl aliquots onto two URA-D platesand incubated at 30° C. After about 72 hours, the Ura+ yeasttransformants from a single plate are resuspended in 1 ml H2O and spunbriefly to pellet the yeast cells. The cell pellet is resuspended in 0.5ml of lysis buffer (2% Triton X-100, 1% SDS, 100 mM NaCl, 10 mM Tris, pH8.0, 1 mM EDTA). The five hundred μl of the lysis mixture is added to anEppendorf tube containing 250 μl acid-washed glass beads and 300 μlphenol-chloroform, is vortexed for 3 minutes, and spun for 5 minutes inan Eppendorf centrifuge at maximum speed. Three hundred μl of theaqueous phase is transferred to a fresh tube, and the DNA isprecipitated with 600 μl ethanol, followed by centrifugation for 30minutes at maximum speed. The tube is decanted and the pellet is washedwith 1 mL of 70% ethanol. The tube is decanted and the DNA pellet isresuspended in 30 μl 10 mM Tris, pH 8.0, 1 mM EDTA.

Transformation of electrocompetent E. coli host cells (DH12S) is doneusing 5 μl of the yeast DNA preparation and 50 μl of E. coli cells. Thecells are electropulsed at 2.0 kV, 25 μF, and 400 ohms. Followingelectroporation, 1 ml SOC (2% Bacto™ Tryptone (Difco, Detroit, Mich.),0.5% yeast extract (Difco), 10 mM NaCl, 2.5 mM KCl, 10 mM MgCl₂, 10 mMMgSO₄, 20 mM glucose) is added and then the cells are plated in 50 μland 200 μl aliquots on two LB AMP plates (LB broth (Lennox), 1.8% Bacto™Agar (Difco), 100 mg/L Ampicillin).

The inserts of three DNA clones for the construct is subjected tosequence analysis and one clone containing the correct sequence isselected. Large scale plasmid DNA is isolated using a commerciallyavailable kit (QIAGEN Plasmid Mega Kit, Qiagen, Valencia, Calif.)according to manufacturer's instructions.

The same process is used to prepare the IL-17RC with a C-terminal histag, composed of Gly Ser Gly Gly His His His His His His (IL-17RCCHIS;SEQ ID NO:51) or the C-terminal FLAG tag, composed of Gly Ser Asp TyrLys Asp Asp Asp Asp Lys (IL-17RCCFLAG; SEQ ID NO:52). To prepare theseconstructs, instead of the 3′ oligonucleotide of SEQ ID NO:50; the 3′oligonucleotide [CAACCCCAGAGCTGTTTTAAGGCGCGCCTCTAGATTAGTGATGGTGATGGTGATGTCCACCAGATCCCTTGTGGATGTATTTGTC; SEQ ID NO:54] is used to generateIL-17RCCHIS or the 3′ oligonucleotide[CAACCCCAGAGCTGTTTTAAGGCGCGCCTCTAGATTACTTATCATCATCATCCTTATAATCGGATCCCTTGTGGATGTATTTGTC; SEQ ID NO:55] is used to generateIL-17RCCFLAG.

Example 7 Transfection and Expression of Soluble IL-17RC ReceptorExpression Constructs that Express the IL-17RC-mFc1 Fusion Protein, andthe IL-17RC-CEE, IL-17RC-CHIS, and IL-17RC-CFLAG C-Terminal TaggedProteins

Three sets of 200 μg of each of the soluble IL-17RC fusion or taggedexpression constructs are separately digested with 200 units of PvuI at37° C. for three hours, precipitated with isopropyl alcohol, andcentrifuged in a 1.5 mL microfuge tube. The supernatant is decanted offthe pellet, and the pellet is washed with 1 mL of 70% ethanol andallowed to incubate for 5 minutes at room temperature. The tube is spunin a microfuge for 10 minutes at 14,000 RPM and the supernatant isdecanted off the pellet. The pellet is then resuspended in 750 μl of CHOcell tissue culture medium in a sterile environment, allowed to incubateat 60° C. for 30 minutes, and is allowed to cool to room temperature.Approximately 5×10⁶ CHO cells are pelleted in each of three tubes andare resuspended using the DNA-medium solution. The DNA/cell mixtures areplaced in a 0.4 cm gap cuvette and electroporated using the followingparameters; 950 μF, high capacitance, at 300 V. The contents of thecuvettes are then removed, pooled, and diluted to 25 mLs with CHO celltissue culture medium and placed in a 125 mL shake flask. The flask isplaced in an incubator on a shaker at 37° C., 6% CO₂ with shaking at 120RPM.

The CHO cells are subjected to nutrient selection followed by stepamplification to 200 nM methotrexate (MTX), and then to 1 μM MTX. Fusionor tagged protein expression is confirmed by Western blot, and the CHOcell pool is scaled-up for harvests for protein purification.

Example 8 Expression of Soluble IL-17RC

An expression plasmid containing IL-17RC-Tbx-C(Fc9) (SEQ ID NO:64) wasconstructed via homologous recombination using a DNA fragment ofIL-17RC_Tbx and the expression vector pZMP40. The fragment was generatedby PCR amplification using primers zc44531 and zc44545.

The PCR fragment IL-17RC_Tbx contains a partial IL-17RC extracellulardomain coding region, which was made using a previously generated cloneof IL-17RC as the template. The fragment includes a 5′ overlap with thepZMP40 vector sequence in the otPA coding region, the IL-17RC segment(amino acid residue 21 to 451 of SEQ ID NO:2), a linker sequence, athrombin cleavage site, and a 3′ overlap with the pZMP40 vector in theFc9 coding region. PCR conditions used were as follows: 1 cycle, 94° C.,5 minutes; 35 cycles, 94° C., 1 minute, followed by 55° C., 2 minutes,followed by 72° C., 3 minutes; 1 cycle, 72° C., 10 minutes.

The PCR reaction mixtures were run on a 1% agarose gel and a bandcorresponding to the sizes of the inserts were gel-extracted using aQIAquick™ Gel Extraction Kit (Qiagen, Cat. No. 28704).

Plasmid pZMP40 is a mammalian expression vector containing an expressioncassette having the MPSV promoter, multiple restriction sites forinsertion of coding sequences, an otPA signal peptide sequence, and thesequence for Fc9; an internal ribosome entry site (IRES) element frompoliovirus, and the extracellular domain of CD8 truncated at theC-terminal end of the transmembrane domain; an E. coli origin ofreplication; a mammalian selectable marker expression unit comprising anSV40 promoter, enhancer and origin of replication, a DHFR gene, and theSV40 terminator; and URA3 and CEN-ARS sequences required for selectionand replication in S. cerevisiae. It was constructed from pZMP21 (PatentPub. No. US 2003/0232414 A1; deposited at the American Type CultureCollection and designated as ATCC# PTA-5266).

The plasmid pZMP40 was cut with BgIII prior to recombination in yeastwith the PCR fragment. One hundred microliters of competent yeast (S.cerevisiae) cells were independently combined with 10 μl of the insertDNA (SEQ ID NO:66) and 100 ng of cut pZMP40 vector, and the mix wastransferred to a 0.2-cm electroporation cuvette. The yeast/DNA mixturewas electropulsed using power supply (BioRad Laboratories, Hercules,Calif.) settings of 0.75 kV (5 kV/cm), ∞ ohms, and 25 μF. Six hundred 0of 1.2 M sorbitol was added to the cuvette, and the yeast was plated ina 100-0 and 3000 aliquot onto two URA-D plates and incubated at 30° C.After about 72 hours, the Ura+ yeast transformants from a single platewere resuspended in 1 ml H₂O and spun briefly to pellet the yeast cells.The cell pellet was resuspended in 0.5 ml of lysis buffer (2% TritonX-100, 1% SDS, 100 mM NaCl, 10 mM Tris, pH 8.0, 1 mM EDTA). The fivehundred microliters of the lysis mixture was added to an Eppendorf tubecontaining 250 μl acid-washed glass beads and 300 μl phenol-chloroform,was vortexed for 3 minutes, and spun for 5 minutes in an Eppendorfcentrifuge at maximum speed. Three hundred microliters of the aqueousphase was transferred to a fresh tube, and the DNA was precipitated with600 μl ethanol (EtOH), followed by centrifugation for 30 minutes atmaximum speed. The tube was decanted and the pellet was washed with 1 mLof 70% ethanol. The tube was decanted and the DNA pellet was resuspendedin 30 μl TE.

Transformation of electrocompetent E. coli host cells (DH12S) was doneusing 5 μl of the yeast DNA prep and 50 μl of cells. The cells wereelectropulsed at 2.0 kV, 25 μF, and 400 ohms. Following electroporation,1 ml SOC (2% Bacto™ Tryptone (Difco, Detroit, Mich.), 0.5% yeast extract(Difco), 10 mM NaCl, 2.5 mM KCl, 10 mM MgCl₂, 10 mM MgSO₄, 20 mMglucose) was added and then the cells were plated in a 50 0 and a 200 0aliquot on two LB AMP plates (LB broth (Lennox), 1.8% Bacto™ Agar(Difco), 100 mg/L Ampicillin).

The inserts of three clones for the construct was subjected to sequenceanalysis and one clone for each construct, containing the correctsequence, was selected. Larger scale plasmid DNA was isolated using acommercially available kit (QIAGEN Plasmid Mega Kit, Qiagen, Valencia,Calif.) according to manufacturer's instructions.

Three sets of 200 μg of the IL-17RC[L21-K451]_Tbx_C(Fc9) construct werethen each digested with 200 units of Pvu I at 37° C. for three hours andthen were precipitated with IPA and spun down in a 1.5 mL microfugetube. The supernatant was decanted off the pellet, and the pellet waswashed with 1 mL of 70% ethanol and allowed to incubate for 5 minutes atroom temperature. The tube was spun in a microfuge for 10 minutes at14,000 RPM and the supernatant was decanted off the pellet. The pelletwas then resuspended in 750 μl of PF-CHO media in a sterile environment,allowed to incubate at 60° C. for 30 minutes, and was allowed to cool toroom temperature. 5×10⁶ APFDXB11 cells were spun down in each of threetubes and were resuspended using the DNA-media solution. The DNA/cellmixtures were placed in a 0.4 cm gap cuvette and electroporated usingthe following parameters: 950 μF, high capacitance, and 300 V. Thecontents of the cuvettes were then removed, pooled, and diluted to 25mLs with PF-CHO media and placed in a 125 mL shake flask. The flask wasplaced in an incubator on a shaker at 37° C., 6% CO₂, and shaking at 120RPM.

The cell line was subjected to nutrient selection followed by stepamplification to 200 nM methotrexate (MTX), and then to 1 μM MTX.Expression was confirmed by western blot, and the cell line wasscaled-up and protein purification followed.

Example 9 Purification of Soluble IL-17RC from CHO Cells

Conditioned media from CHO cells expressing IL-17RC-TbX-Fc9 (SEQ IDNO:64) was concentrated approximately 10-fold with a Pellicon-IItangential flow system against two Biomax 0.1 m2 30 kD molecular weightcutoff membrane cassettes (Millipore, Bedford, Mass.). The concentratedmedia was pH adjusted to 5.5 with glacial acetic acid, 0.2 μm sterilefiltered then loaded onto a Protein G sepharose fast flow resin(Pharmacia, Piscataway, N.J.) via batch chromatography overnight at 4 C.Prior to loading the pH adjusted conditioned media, the Protein G resinwas pre-equilibrated with, 5 column volumes (approximately 150 ml) of 25mM sodium acetate, 150 mM NaCl, pH5.5. The ratio of filtered, pHadjusted conditioned media to resin was 33:1 (v/v).

The batched chromatography process was performed at ambient roomtemperature (approximately 21 C). The batched, pH adjusted, 0.22 μmfiltered, conditioned media was poured into an empty 5.5×20.5 cm glasscolumn (BioRad, Hercules, Calif.) and packed via gravity. The column waswashed with 10 column volumes (approximately 300 ml) of 25 mM sodiumacetate, 150 mM NaCl, pH5.5. Bound protein was then pH eluted with 100mM glycine, pH 2.7. 9.0 ml fractions were collected and immediatelyneutralized with 1.0 ml 2.0M Tris, pH 8.0. The collected fractions wereanalyzed via SDS-PAGE Coomassie staining. Fractions containingIL-17RC-Tbx-Fc9 were pooled and concentrated approximately 6-fold usinga 5 kD molecular weight cutoff Biomax membrane spin concentrator(Millipore, Bedford, Mass.) according to the manufacturer'sinstructions.

The pooled, concentrated fractions were then dialyzed, at 4 C,extensively against 1× phosphate buffered saline, pH 7.3 (Sigma, St.Louis, Mo.) using a 7 kD molecular weight cutoff membrane Slide-A-Lyzer(Pierce, Rockford, Ill.). IL-17RC-TbX-Fc9 as formulated in 1× phosphatebuffered saline, pH 7.3 was 0.22 μm sterile filtered prior to aliquotingand storage at −80° C.

Example 10 Binding of IL-17A and IL-17F to Human IL-17RC A) Binding ofBiotinylated Cytokines to Transfected Cells

Baby Hamster Kidney (BHK) cells that had been transfected withexpression vectors encoding human IL-17 receptor (SEQ ID NO:21), humanIL-17RC (SEQ ID NO:2), or both of these receptors are assessed for theirability to bind biotinylated human IL-17A and human IL-17F. Cells areharvested with versene, counted and diluted to 107 cells per ml instaining media (SM), which is HBSS plus 1 mg/ml bovine serum albumin(BSA), 10 mM Hepes, and 0.1% sodium azide (w/v). Biotinylated humanIL-17A (SEQ ID NO:14) and human IL-17F (SEQ ID NO:16) are incubated withthe cells on ice for 30 minutes at various concentrations. After 30minutes, excess cytokine is washed away with SM and the cells areincubated with a 1:100 dilution of streptavidin conjugated tophycoerythrin (SA-PE) for 30 minutes on ice. Excess SA-PE is washed awayand cells are analyzed by flow cytometry. The amount of cytokine bindingwas quantitated from the mean fluorescence intensity of the cytokinestaining. From this analysis, we find that human IL-17A binds both thehuman IL-17R and IL-17RC to a similar extent. Also, human IL-17F bindsIL-17RC to a similar level, but binds IL-17R detectably, but to a muchlower level than was seen with IL-17A.

B) Binding of Biotinylated Cytokines to Human Peripheral BloodMononuclear Cells

Human peripheral blood mononuclear cells (PBMC) were prepared from wholeblood by ficoll density gradient centrifugation. PBMC at 107 cells perml were simultaneously incubated with biotinylated IL-17A or IL-17F at 1μg/ml and fluorochrome conjugated antibodies to specific cell surfaceproteins that were designed to distinguish various white blood celllineages. These markers include CD4, CD8, CD19, CD11b, CD56 and CD16.Excess antibody and cytokine are washed away, and specific cytokinebinding is detected by incubating with SA-PE as described above. Sampleswere analyzed by flow cytometry and from this analysis, we find thathuman IL-17A binds to virtually all PBMC populations examined, but thathuman IL-17F does not detectably bind to any population.

C) Inhibition of Specific Binding of Biotinlyated Human IL-17a andIL-17F with Unlabeled Cytokine

Binding studies are performed as discussed above, but excess unlabeledhuman IL-17A and IL-17F are included in the binding reaction. In studieswith BHK cells, the amount of unlabeled cytokine was varied over a rangeof concentrations and we find that addition of unlabeled IL-17A competedfor binding of both IL-17A and IL-17F to both IL-17RC and IL-17R.However, unlabeled IL-17F competed for binding of both IL-17A and IL-17Fto IL-17RC, but it did not compete effectively for binding to IL-17R.This indicates that both IL-17A and IL-17F specifically bind to IL-17RC,and that they bind at a site that is either identical or overlapssignificantly since they cross-compete for binding. Also, IL-17Acompetes for the relatively weak binding of IL-17F for IL-17R,indicating these two cytokines also bind to a similar region in theIL-17R, but IL-17F binds IL-17R with much reduced affinity relative toIL-17RC.

D) Inhibition of Specific Binding of Biotinylated Human IL-17a andIL-17F with Soluble IL-17RC and IL-17R

Binding studies are performed as discussed above, except that a solubleform of IL-17RC or IL-17R are included in the binding reactions. Thesesoluble receptors are fusion proteins derived from the extracellulardomain of each receptor fused to the human IgG1 constant (Fc) region. Wefind that soluble IL-17RC inhibits binding of both human IL-17A andIL-17F to both IL-17R and IL-17RC transfected BHK cells. However,soluble IL-17R inhibits binding of IL-17A to either receptor, but doesnot effectively block binding of IL-17F to IL-17RC, consistent with thepoor binding of IL-17F for the IL-17R.

Example 11 IL-17A and IL-17F Bind to IL-17RC

A) Binding Inhibition with Cold Ligand

BHK cells transfected with hIL-17RC (SEQ ID NO:2) and IL-17R (SEQ IDNO:21) were plated at 40,000 cells/well in a 24-well dish (Costar 3527)two days prior to assay. IL-17A (SEQ ID NO:14) and IL-17F (SEQ ID NO:16)that had been radiolabeled by the iodobead method were addedindependently to wells in triplicate at 10 ng/ml with a total of 250ul/well in binding buffer (RPMI 1640 media (JRH 51502-500M) with 10mg/ml bovine serum albumin (Gibco15260-037)). Cold competitors wereadded in 100 fold molar excess. Competitors tested included IL-17A,IL-17B, IL-17C, IL-17D, IL-17E, IL-17F and IL-21. Wells were incubatedon ice for 1-hour followed by two washes with PBS (Invitrogen 20012-027)and one wash with a high salt solution (1.5M NaCL, 50 mM HEPES pH 7.4).Wells were extracted with 500 ul of 0.8M NaOH for 30 min. at roomtemperature and counts per minute were measured in a gamma counter(Packard Cobra II A5005).

The results indicated that 100× molar cold IL-17A and IL-17F were ableto reduce binding of 125I IL-17A to BHK hIL-17RC by approximately 7 foldwhile IL-17B,C,D,E and IL-21 had no effect on binding. 100× molar coldIL-17A reduced the binding of 125I IL-17A to BHK IL-17R by approximately4 fold while IL-17B,C,D,E,F and IL-21 had no effect on binding. 100×molar cold IL-17A and IL-17F reduced the binding of 125IL-17F to BHKhIL-17RC by approximately 4 fold and 5 fold, respectively, whileIL-17B,C,D,E and IL-21 had no effect on binding.

B) Binding Inhibition with Soluble Receptor:

Binding to hzytorl4 (SEQ ID NO:2) and IL-17R (SEQ ID NO:21) transfectedBHK cells was performed as in one, but 100 fold molar excess solublehIL-17RCx1/Fc9 (Example 8) and soluble IL-17R/Fc (obtained from R&D;Ref. 177-IRi) were used in place of cold ligand in the competition.Cells were washed, extracted and counted as in part one.

Soluble hIL-17RC/Fc inhibited binding of 125IL-17F to BHK hIL-17RC withan IC50 of 10× molar excess average from three experiments. SolublehIL-17RC/Fc inhibition of 125IIL-17A on the same cell line gave anaverage IC50 of 20× molar excess and soluble IL-17R/Fc inhibition of125I IL-17A gave an average IC50 of 20× molar excess.

C) Binding Saturation

Transfected BHK cells were plated into 24-well dishes as in one.Radiolabeled IL-17A and IL-17F were added starting at a concentration of4 nM in eight 1:3 dilutions (to a concentration of 1.83 μM) intriplicate with a total of 250 μl/well in binding buffer. Separately,100 fold molar excess of cold ligand was added at each dilution point.Cells were washed, extracted and counted as in one. Specific counts perminute were plotted against concentration of radiolabeled ligand addedby subtracting the 100 fold excess counts from the uncompeted counts ateach dilution point. These normalized data were plotted to generatesaturation binding curves for each combination of radiolabeled ligandand transfected BHK cells. Table 7 shows the affinity values calculatedfrom all three experiments.

TABLE 7 125I IL-17A + BHK hIL-17RC 125I IL-17A + BHK IL-17R 1. 180 pM 1.2.5 +/− 0.2 nM 2. 200 pM 2. 4.5 +/− 0.3 nM 3. 370 pM 3. 5.9 +/− 0.1 nM125I IL-17F + BHK hIL-17RC 125I IL-17F + BHK IL-17R 1. 50 pM 1. Very lowaffinity 2. 60 pM 2. Very low affinity 3. 80 pM 3. Very low affinity

One-site binding curve fits agreed most closely with IL-17A & IL-17Fbinding to IL-17R. Two-site binding curve fits agreed most closely withIL-17A and IL-17F binding to hIL-17RC. The high affinity binding site isthe value shown above. The low affinity binding site had very lowaffinity and varied widely between the three experiments.

Example 12 Murine Nih3t3 Cells Respond to Human IL-17A and IL-17F

A) Cell plating and kz 142 Adenovirus Reporter Infection.

Nih3t3 cells, derived from mouse fibroblasts (described in ATCC) Nih3t3were plated at 5000 cells/well in solid white, cell culture coated 96well plates, (Cat. #3917. Costar) using DMEM/10% FBS, containingglutamine and amended with pyruvate and cultured overnight at 37° C. and5% CO₂. On this second day, the plating media was removed and Kz142adenovirus particles at a multiplicity of infection of 5000particles/cell were prepared in DMEM/1% FBS, containing glutamine andamended with pyruvate and cultured overnight at 37° C. and 5% CO₂.

B) Luciferase Assay Measuring IL-17A and F Activation of kz142Adenovirus Reporter Infected nih3t3 Cells.

Following the overnight incubation with the adenovirus particlereporter, human IL-17A and IL-17F Ligand treatments were prepared inserum free media amended to 0.28% BSA. The adenovirus particles andmedia were removed and the appropriate ligand doses were given intriplicates. Incubation at 37° C. and 5% CO₂ was continued for 4 hours,after which the media was removed, cells lysed for 15 minutes and meanfluorescence intensity (MFI) measured using the luciferase assay systemand reagents. (Cat.#e1531 Promega. Madison, Wis.) and a Microplateluminometer. Activity was detected at concentrations ranging from0.1-1000 ng/ml human IL-17A and IL-17F, generating EC50 values of about50 ng/ml for both ligands. These data suggest that nih3t3 cells carryreceptors to these ligands and that IL-17A and IL-17F activate theNF-κB/Ap-1 transcription factor.

Example 13 Murine Nih3t3 Cells Express Both IL-17RA and IL-17RC

RTPCR analysis of nih3t3 RNA demonstrated that these cells are positivefor both IL-17 RA and IL-17RC, consistent with their NF-κB/Ap-1 responseto human IL-17A and IL-17F mediation being mediated through one or bothof these receptors.

RTPCR Details: A) Murine IL-17RC PCR

First strand cDNA was prepared from total RNA isolated from nih3t3 cellsusing standard methods. PCR was applied using hot star polymerase andthe manufacturer's recommendations (Qiagen, Valencia, Calif.) usingsense primer, zc38910, 5′ ACGAAGCCCAGGTACCAGAAAGAG 3′ (SEQ ID NO:56) andantisense primer, zc 38679, 5′ AAAAGCGCCGCAGCCAAGAGTAGG 3′ (SEQ IDNO:57) and 35 cycles of amplification. Agarose gel electrophoresisrevealed a single, robust amplicon of the expected, 850 bp size.

B) Murine IL-17RA PCR

First strand cDNA was prepared from total RNA isolated from nih3t3 cellsusing standard methods. PCR was applied using hot star polymerase andthe manufacturer's recommendations (Qiagen, Valencia, Calif.) usingsense primer, zc38520, 5′ CGTAAGCGGTGGCGGTTTTC 3′ (SEQ ID NO:58) andantisense primer, zc 38521, 5′ TGGGCAGGGCACAGTCACAG 3′ (SEQ ID NO:59)and 35 cycles of amplification. Agarose gel electrophoresis revealed asingle, robust amplicon of the expected, 498 bp size.

Example 14 Creation of a Stable Nih3t3 Assay Clone Expressing theap1/nfkb Transcription Factor

The murine nih3t3 cell line described above was stably transfected withthe kz142 ap1/nfkb reporter construct, containing a neomycin-selectablemarker. The Neo resistant transfection pool was plated at clonaldensity. Clones were isolated using cloning rings and screened byluciferase assay using the human IL-17A ligand as an inducer. Cloneswith the highest mean fluorescence intensity (MFI) (via Ap-1/NF-κBluciferase) and the lowest background were selected. A stabletransfectant cell line was selected and called nih3t3/kz142.8.

Example 15 Inhibition of Activation by Human IL-17A and IL-17F in MurineNih3t3 Cells Using Soluble IL-17RC and IL-17RA/FC Chimeras

Soluble forms of IL-17RC or IL-17RA were used as antagonists of humanIL-17A and IL-17F activation of Ap-1/NF-κB elements in a luciferaseassay. These soluble receptors are fusion proteins derived from theextracellular domain of each receptor fused to the human IgG1 constant(Fc) region. The soluble human IL-17R FC fusion protein was purchased.(recombinant human IL-17R/FC chimera, catalog number 177-1R-100, R&DSystems, Inc., Minneapolis, Mn.) The soluble human IL-17RC FC chimera(IL-17RCsR/FC9) was constructed as described above. We find that anexcess IL-17RCsR/FC9 and human IL17RsR/FC chimera inhibit EC50 levels ofboth human IL-17A and IL-17F mediation of Ap-1/NF-κB activation of themurine nih3t3/kz142.8 assay cell line.

The IL-17RCsR/FC9 protein showed the greatest potency in antagonizingIL-17F activation and IL17RsR/FC chimera showed the greatest potency inantagonizing IL-17A activation.

Example 16 IL-17F mRNA is Upregulated in a Murine Model of Asthma

IL-17F mRNA levels were measured in a sensitization and airway challengemodel in mice. Groups of mice, 8 to 10 wks of age, were sensitized byintraperitoneal injection of 10 ug of recombinant Dermatophagoidespteronyssinus allergen 1 (DerP1) (Indoor biotechnologies, Cardiff, UK)in 50% Imject Alum (Pierce) on days 0 and 7. Seven days later, mice werechallenged on 3 consecutive days (days 14, 15 and 16) with 20 μg ofDerP1 in 50 μl PBS. There were 4 mice representing this group. Negativecontrols included 5 mice given phosphate buffered saline (PBS)sensitization, followed by PBS challenge. In addition to 3 mice givenDerP1 sensitization, followed by PBS challenge. Forty-eight hoursfollowing allergen, or control challenge whole lung tissue was harvestedand total RNA was isolated.

First strand cDNA was prepared using identical amounts of total RNA fromeach subject. IL-17F PCR was applied using Qiagen hotstar polymerase(Qiagen, Valencia, Calif.) and the manufacturer's recommendations. TheIL-17F PCR utilized 35 cycles of amplification with sense primer,zc46098, 5′ ACTTGCCATTCTGAGGGAGGTAGC 3′ (SEQ ID NO:60) and antisenseprimer, 46099, 5′ CACAGGTGCAGCCAACTTTTAGGA 3′ (SEQ ID NO:61). In orderto establish that the template quality was uniform amongst all subjects,Beta Actin PCR was applied to the same amount of each template used inthe IL-17F amplification. B actin PCR included 25 cycles of PCR withsense primer, zc44779, 5′ GTGGGCCGCTCTAGGCACCA 3′ (SEQ ID NO:62) andantisense primer, zcc44776, 5′ CGGTTGGCCTTAGGGTTCAGGGGGG 3′ (SEQ IDNO:63).

All 4 mice from the DerP1 sensitized, DerP1 challenged treatment group(the asthma simulation) showed robust IL-17F amplification. In contrast,weak IL-17F amplification was seen from the negative controls, including3 of 3 subjects representing the DerP1 sensitized/PBS challengedtreatment group and 5 of 5 subjects from the PBS sensitized/PBSchallenged treatment group. B actin amplification was at least as robustfor the negative controls as for the asthma-simulated subjects,demonstrating that the weak negative control IL-17F amplification wasnot due to template problems.

Example 17 COS Cell Transfection and Secretion Trap

A) Cos Cell Transfection and Secretion Trap Assays Show thatIL-17RCsR/Fc9 and IL-17F is a Receptor/Ligand Pair

A secretion trap assay was used to match the human IL-17RC (SEQ ID NO:2)to the human IL-17F (SEQ ID NO:16). The soluble IL-17RCsR/Fc9 fusionprotein (Example 8) was used as a binding reagent in a secretion assay.SV40 on containing expression vectors containing cDNA of humanIL-17B,C,D,E, and F was transiently transfected into COS cells. Thebinding of IL-17RCsR/Fc9 to transfected COS cells was carried out usingthe secretion trap assay described below. Positive binding ofIL-17RCsR/Fc9 was only seen to human IL-17F. These results demonstratethe novel finding that human IL-17RC and IL-17F is a receptor/ligandpair.

B) COS Cell Transfections

The COS cell transfection was performed as follows: Mix 3 ul pooled DNAand 5 ul Lipofectamine™ in 92 μl serum free DMEM media (55 mg sodiumpyruvate, 146 mg L-glutamine, 5 mg transferrin, 2.5 mg insulin, 1 μgselenium and 5 mg fetuin in 500 ml DMEM), incubate at room temperaturefor 30 minutes and then add 400 ul serum free DMEM media. Add this 500ul mixture onto 1.5×10⁵ COS cells/well plated on 12-well tissue cultureplate and incubate for 5 hours at 37° C. Add 500 ul 20% FBS DMEM media(100 ml FBS, 55 mg sodium pyruvate and 146 mg L-glutamine in 500 mlDMEM) and incubate overnight.

C) Secretion Trap Assay

The secretion trap was performed as follows: Media was rinsed off cellswith PBS and then fixed for 15 minutes with 1.8% Formaldehyde in PBS.Cells were then washed with TNT (0.1M Tris-HCL, 0.15M NaCl, and 0.05%Tween-20 in H2O), and permeated with 0.1% Triton-X in PBS for 15minutes, and again washed with TNT. Cells were blockd for 1 hour withTNB (0.1M Tris-HCL, 0.15M NaCl and 0.5% Blocking Reagent (NENRenaissance TSA-Direct Kit) in H2O), and washed again with TNT. Thecells were incubated for 1 hour with 1 μg/ml human IL-17RCx 1 sR/FC9soluble receptor fusion protein Cells were then washed with TNT. Cellswere incubated for another hour with 1:200 diluted goat-anti-humanIg-HRP (Fc specific). Again cells were washed with TNT.

Positive binding was detected with fluorescein tyramide reagent diluted1:50 in dilution buffer (NEN kit) and incubated for 4-6 minutes, andwashed with TNT. Cells were preserved with Vectashield Mounting Media(Vector Labs Burlingame, Calif.) diluted 1:5 in TNT. Cells werevisualized using a FITC filter on fluorescent microscope.

Example 18 Generation of Murine Anti-Human IL-17RC Monoclonal Antibodies

A) Immunization for generation of anti-IL-17RC Antibodies

1. Soluble IL-17RC-muFc

Six to twelve week old intact or IL-17RC knockout mice are immunized byintraperitoneal injection with 25-50 ug of soluble human IL-17RC-muFcprotein (Example 23) mixed 1:1 (v:v) with Ribi adjuvant (Sigma) on abiweekly schedule. Seven to ten days following the third immunization,blood samples were taken via retroorbital bleed, the serum harvested andevaluated for its ability to inhibit the binding of IL-17 or IL-17F toIL-17RC in neutralization assays (e.g., described herein) and to stainIL-17RC transfected versus untransfected 293 cells in a FACS stainingassay. Mice continued to be immunized and blood samples taken andevaluated as described above until neutralization titers reached aplateau. At that time, mice with the highest neutralization titers wereinjected intravascularly with 25-50 μg of soluble IL-17RC-Fc protein inPBS. Three days later, the spleen and lymph nodes from these mice wereharvested and used for hybridoma generation, for example using mousemyeloma (P3-X63-Ag8.653.3.12.11) cells or other appropriate cell linesin the art, using standard methods known in the art (see, e.g., Kearney,J. F. et al., J. Immunol. 123:1548-50, 1979; and Lane, R. D. J ImmunolMethods 81:223-8, 1985).

2. Soluble IL-17RC, IL-17RC-CEE, IL-17RC-CHIS, IL-17RC-CFLAG

Six to twelve week old intact or IL-17RC knockout mice are immunized byintraperitoneal injection with 25-50 ug of soluble human IL-17RC-CEE,IL-17RC-CHIS, or IL-17RC-CFLAG mixed 1:1 (v:v) with Ribi adjuvant(Sigma) on a biweekly schedule. Seven to ten days following the thirdimmunization, blood samples are taken via retroorbital bleed, the serumharvested and evaluated for its ability to inhibit the binding of IL-17or IL-17F to IL-17RC in neutralization assays (e.g., described herein)and to stain IL-17RC transfected versus untransfected 293 cells in aFACS staining assay. Mice are continued to be immunized and bloodsamples taken and evaluated as described above until neutralizationtiters reached a plateau. At that time, mice with the highestneutralization titers are injected intravascularly with 25-50 ug ofsoluble IL-17RC, IL-17RC-CEE, zcytor-CHIS, or IL-17RC-CFLAG antigenprotein in PBS. Three days later, the spleen and lymph nodes from thesemice are harvested and used for hybridoma generation, for example usingmouse myeloma (P3-X63-Ag8.653.3.12.11) cells or other appropriate celllines in the art, using standard methods known in the art (e.g., seeKearney, J. F. et al., J. Immunol. 123:1548-50, 1979; and Lane, R. D. JImmunol Methods 81:223-8, 1985).

3. P815 Transfectants that Express the IL-17RC

Six to ten week old female DBA/2 mice are immunized by intraperitonealinjection of 1×10⁵ live, transfected P815 cells, for exampleP815/IL-17RC cells (e.g., 0.5 ml at a cell density of 2×10⁵ cells/ml).Prior to injection, the cells are maintained in the exponential growthphase. For injection the cells are harvested, washed three times withPBS and then resuspended in PBS to a density of 2×10⁵ cells/ml. In thismodel, the mice develop an ascites tumor within 2-3 weeks and progressto death by 4-6 weeks unless an immune response to the transfectedtarget antigen has been mounted. At three weeks mice with no apparentabdominal swelling (indicative of ascites) are re-immunized as above at2-3 week intervals. Seven to ten days following the second immunization,blood samples are taken via retroorbital bleed, the serum harvested andevaluated for its ability to inhibit the binding of IL-17 or IL-17F toIL-17 or IL-17RC in neutralization assays (e.g., described herein) andto stain IL-17RC transfected versus untransfected 293 cells in a FACSstaining assay. Mice continue to be immunized and blood samples takenand evaluated as described above until neutralization titers reach aplateau. At that time, the mice with the highest neutralization titersare injected intraperitonealy with 1×10⁵ live, transfected P815 cells.Four days later, the spleen and lymph nodes from these mice areharvested and used for hybridoma generation, for example using mousemyeloma (P3-X63-Ag8.653.3.12.11) cells or other appropriate cell linesin the art, using standard methods known in the art (see, e.g., Kearney,J. F. et al., supra.; and Lane, R. D. supra.).

An alternative to the above immunization scheme with live, transfectedP815 cells involves intraperitoneal injection of 1-5×10⁶ irradiated,transfected cells every 2-3 weeks. In this approach, no animals developand die of ascites. Instead, animals are monitored for a neutralizingimmune response to IL-17RC in their serum as outlined above, startingwith a bleed after the second immunization. Once neutralization titershave reached a maximal level, the mice with highest titers are given apre-fusion, intraperitoneal injection of 5×10⁶ irradiated cells and fourdays later, the spleen and lymph nodes from these mice are harvested andused for hybridoma generation, for example using mouse myeloma(P3-X63-Ag8.653.3.12.11) cells or other appropriate cell lines in theart, using standard methods known in the art (see, e.g., Kearney, J. F.et al., supra.; and Lane, R. D. supra.).

B) Screening the Hybridoma Fusions for Antibodies that bind IL-17RC andInhibit the Binding of IL-17 or IL-17F to IL-17RC

Three different primary screens are performed on the hybridomasupernatants at 8-10 days post-fusion. For the first assay, antibodiesin supernatants were tested for their ability to bind to plate boundsoluble human IL-17RC, IL-17RC-muFc, IL-17RC-CEE, IL-17RC-CHIS, orIL-17RC-CFLAG protein by ELISA using HRP-conjugated goat anti-mousekappa and anti-lambda light chain second step reagents to identify boundmouse antibodies. To demonstrate specificity for the IL-17RC portion ofthe IL-17RC fusion proteins, positive supernatants in the initial assaywere evaluated on an irrelevant protein fused to the same murine Fcregion (mG2a), EE sequence, HIS sequence, or FLAG sequence. Antibody inthose supernatants that bound to IL-17RC-fusion protein and not theirrelevant muFc or other proteins containing fusion protein sequencewere deemed to be specific for IL-17RC. For the second assay, antibodiesin all hybridoma supernatants were evaluated by ELISA for their abilityto inhibit the binding of biotinylated human IL-17 or biotinylated humanIL-17F to plate bound IL-17RC-muFc or IL-17RC-fusion proteins.

All supernatants containing antibodies that bound specifically toIL-17RC, whether they inhibited the binding of IL-17 or IL-17F toIL-17RC or not in the ELISA assay, were subsequently tested for theirability to inhibit the binding of IL-17 or IL-17F to IL-17RC transfectedBaf3 or BHK cells or normal human bronchial epithelial cells. Allsupernatants that were neutralization positive in either the IL-17 orIL-17F inhibition assays or both the IL-17 and IL-17F inhibition assayswere subsequently evaluated for their ability to stain IL-17RCtransfected versus non-transfected Baf3 or BHK cells by FACS analysis.This analysis was designed to confirm that inhibition of IL-17 or IL-17Fbinding to IL-17RC, was indeed due to an antibody that specificallybinds the IL-17RC receptor. Additionally, since the FACS analysis wasperformed with an anti-IgG second step reagent, specific FACS positiveresults indicate that the neutralizing antibody was likely to be of theIgG class. By these means, a master well was identified that boundIL-17RC in the plate bound ELISA, inhibited the binding of IL-17 orIL-17F to IL-17RC in the ELISA based inhibition assay, blocked theinteraction of IL-17 and IL-17F with IL-17RC transfected Baf3 or BHKcells, respectively, and was strongly positive for the staining ofIL-17RC transfected Baf3 or BHK cells with an anti-mouse IgG second stepreagent.

The third assay consists of primary human bronchial epithelial cellswhich express IL-17RC and can be induced to secrete IL-8 or IL-6 inresponse to IL-17F treatment. The specific monoclonal antibody isassayed by its ability to inhibit the IL-17 or IL-17F stimulated IL-8 orIL-6 production by these cells. IL-8 and IL-6 production is assayed inresponse to IL-17 or IL-17F as described herein.

Alternatively, the monoclonal antibody; anti-IL-17RC, mediatedinhibition of IL-17 or IL-17F induced luciferase production in NIH 3T3or other IL-17RC containing cells can be used with or in place of one ofthe bioactivity neutralization assays noted above. The NF-κB mediatedluciferase assay in NIH 3T3 cells is described herein.

C) Cloning Anti-IL-17RC Specific Antibody Producing Hybridomas

Hybridoma cell lines producing a specific anti-IL-17RC mAb thatcross-neutralized the binding of IL-17 and IL-17F to appropriatelytransfected BaF3 or BHK cells are cloned by a standard low-densitydilution (less than 1 cell per well) approach. Approximately 5-7 daysafter plating, the clones are screened by ELISA on, for example, platebound human IL-17RC-muFc followed by a retest of positive wells by ELISAon irrelevant muFc containing fusion protein as described above.Selected clones, whose supernatants bind to IL-17RC-muFc and not theirrelevant muFc containing fusion protein, are further confirmed forspecific antibody activity by repeating both neutralization assays aswell as the FACS analysis. All selected IL-17RC antibody positive clonesare cloned a minimum of two times to help insure clonality and to assessstability of antibody production. Further rounds of cloning areperformed and screened as described until, preferably, at least 95% ofthe resulting clones were positive for neutralizing anti-IL-17RCantibody production.

D) Biochemical Characterization of the Molecule Recognized byAnti-IL-17RC mAbs

Biochemical confirmation that the target molecule, IL-17RC, recognizedby the putative anti-IL-17RC mAbs is indeed IL-17RC are performed bystandard immunoprecipitation followed by SDS-PAGE analysis or westernblotting procedures, both employing soluble membrane preparations fromIL-17RC transfected versus untransfected Baf3 or BHK cells. Moreover,soluble membrane preparations of non-transfected cell lines that expressIL-17RC are used show that the mAbs recognize the native receptor chainas well as the transfected one. Alternatively, the mAbs are tested fortheir ability to specifically immunoprecipitate or western blot thesoluble IL-17RC-muFc protein.

Example 19 Neutralization of Human IL-17RC by Sera from Mice Injectedwith P815 Cells Transfected with Human IL-17RC

Using a cell based neutralization assay, serum from mice injected withlive human IL-17RC transfected P815 cells (Example 17) is added as aserial dilution at 1%, 0.5%, 0.25%, 0.13%, 0.06%, 0.03%, 0.02%, and 0%.The assay plates are incubated at 37° C., 5% CO₂ for 4 days at whichtime Alamar Blue (Accumed, Chicago, Ill.) is added at 20 μl/well. Platesare again incubated at 37° C., 5% CO₂ for 16 hours. Results showed thatserum from four of the animals could neutralize signaling of bothhuIL-17 and huIL-17F through human IL-17RC.

Results such as these provide additional evidence that effectivelyblocking IL-17RC by binding, blocking, inhibiting, reducing,antagonizing or neutralizing IL-17 or IL-17F activity (individually ortogether), for example via a neutralizing monoclonal antibody to IL-17RCof the present invention, could be advantageous in reducing the effectsof IL-17 and IL-17F (alone or together) in vivo and may reduce IL-17and/or IL-17F-induced inflammation, such as that seen in, for example inpsoriasis, IBD, colitis, chronic obstructive pulmonary disease, cysticfibrosis or other inflammatory diseases induced by IL-17, and or IL-17Fincluding IBD, arthritis, asthma, psoriatic arthritis, colitis,inflammatory skin conditions, and atopic dermatitis.

Example 20 Pharmacokinetics of an Anti-human IL-17RC Monoclonal Antibody

The test monoclonal antibody, anti-human IL-17RC mAb, is provided in,for example, 3×3 mL aliquots at a concentration of approximately 1 mg/mL(determined by UV Absorbance at 280 nM) and was stored at −80° C. untiluse. The vehicle is 1×PBS (50 mM NaPO₄, 109 mM NaCl), pH 7.3. The mAb isthawed at room temperature before use and aliquots 1 and 2 are used asprovided for the 100 μg IV and SC dosing groups, respectively. Half ofaliquot 3 is diluted 1:2 in 1×PBS for the 50 μg SC dose group and thesecond half of aliquot 3 is diluted 1:10 in 1×PBS for the 10 μg SC dosegroup. Female SCID mice (n=96) are obtained from Charles River Labs.Animals are checked for health on arrival and group-housed (3 animalsper cage). The mice are 12 weeks old with an average body weight ofapproximately 22 g at the beginning of the study.

A) Dosing Protocol

Female SCID mice (n=24/dose group) are randomly placed into four dosinggroups (Table 8). Group 1 was administered the anti-human IL-17RC mAbvia IV injection of approximately 93 μL in a tail vein and Groups 2, 3,and 4 are administered the mAb via SC injection of approximately 93 μLin the scruff of the neck.

B) Sample Collection

Prior to blood collection, mice were fully anesthetized with halothaneor isofluorane. Blood samples were collected via cardiac stick for alltime points except the 168 hr timepoint (collected via eye bleed and thesame animals were bled again at the 504 hr timepoint via cardiac stick).Blood was collected into serum separator tubes and allowed to clot for15 minutes. Samples were subsequently centrifuged for 3 minutes at14,000 rpm. Following centrifugation, aliquots of 125-150 uL weredispensed into labeled eppendorf tubes and immediately stored at −80° C.until analysis.

TABLE 8 Group # Dose (ROA) Animals PK Timepoints 1 100 μg (IV) 3mice/timepoint* 0.25, 1, 4, 8, 24, 72, 168, 336 and 504 hr 2 100 μg (SC)3 mice/timepoint* 0.25, 1, 4, 8, 24, 72, 168, 336 and 504 hr 3  50 μg(SC) 3 mice/timepoint* 0.25, 1, 4, 8, 24, 72, 168, 336 and 504 hr 4  10μg (SC) 3 mice/timepoint* 0.25, 1, 4, 8, 24, 72, 168, 336 and 504 hr*The same animals were used for the 168 and 504 hr timepoints.

C) Quantification of Serum Anti-human IL-17RC mAb Concentrations byELISA

An Enzyme Linked Immunosorbant Assay (ELISA) is developed and qualifiedto analyze mouse serum samples from animals dosed with anti-IL-17RC mAbduring pharmacokinetic studies. This assay is designed to take advantageof a commercially available secondary antibody and colorimetricdetection using TMB. The dilutions used for the standard curve weremodified to improve the definition of the linear portion of the standardcurve. A standard curve in the range of 100 ng/mL to 0.231 ng/mL with2-fold dilutions allows for quantitation of the mouse serum samples. QCsamples are diluted to 1:100, 1:1000 and 1:10000 in 10% SCID mouse serumand back calculated from the standard curve.

D) Pharmacokinetic Analysis

Serum concentration versus time data are downloaded into WinNonlinProfessional 4.0 software (Pharsight, Inc.; Cary, N.C.) forpharmacokinetic analysis. Noncompartmental analysis is used to determinepharmacokinetic parameters based on the mean data at each time point.

Example 21 Neutralization of IL-17A and IL-17F Activity by a Anti-HumanIL-17RC Monoclonal Antibody

Using a cell-based neutralization assay, a purified mouse anti-humanIL-17RC monoclonal antibody is added as a serial dilution, for example,at 10 μg/ml, 5 μg/ml, 2.5 μg/ml, 1.25 μg/ml, 625 ng/ml, 313 ng/ml, 156ng/ml and 78 ng/ml. The assay plates are incubated at 37° C., 5% CO₂ for4 days at which time Alamar Blue (Accumed, Chicago, Ill.) is added at20W/well. Plates are again incubated at 37° C., 5% CO₂ for 16 hours.This assay is able to demonstrate that the purified anti-human IL-17RCmonoclonal antibody is able neutralize signaling of both huIL-17 andhuIL-17F through human IL-17RC. For highly effective antibodies, whenused at approx. 10 μg/ml concentration, the antibody completelyneutralizes proliferation induced by huIL-17 or huIL-17F, with theinhibition of proliferation decreasing in a dose dependent fashion atthe lower concentrations. An isotype-matched negative control mouse mAb,tested at the concentrations described above, is exacted to provide noinhibition of proliferation of either cytokine. These results are ableto further demonstrate that monoclonal antibodies to IL-17RC couldindeed antagonize the activity of the pro-inflammatory ligands, IL-17and IL-17F at low concentrations.

Example 22 IL-17A Induces Elevated Levels of IFN-gamma and TNF-alpha inHuman Peripheral Blood Mononuclear Cells

Human peripheral blood mononuclear cells (PBMC) are purified by ficolldensity gradient centrifugation and then incubated overnight at 37° C.in media alone, 50 ng/ml anti-human CD3 antibody, or the combination of50 ng/ml anti-human CD3 antibody plus 1 μg/ml anti-human CD28 antibody.Replicate cultures for each of these conditions are set up and are givenno cytokine, 25 ng/ml human IL-17A, or 25 ng/ml human IL-17F. After24-hour incubations, supernatants from each culture are harvested andassayed for cytokine content using B-D Bioscience's human Th1/Th2Cytometric Bead Array (CBA). We found that cultures that had beenstimulated with either anti-CD3 or anti-CD3 plus anti-CD28 and had beensupplemented with IL-17A contained significantly elevated levels ofIFN-gamma and TNF-alpha (3-5-fold elevation of each) over cultures withno cytokine added or those that received IL-17F. Cultures in which noanti-CD3 stimulation was added did not show significant changes incytokine levels. In addition, IL-17A addition induced no significantchanges in other cytokines assayed for with the CBA including IL-2,IL-4, IL-5, and IL-10. This data indicates that IL-17A, but not IL-17F,can augment the production of IFN-gamma and TNF-alpha in PBMC culturesstimulated with anti-CD3 or anti-CD3 plus anti-CD28.

Example 23 The Murine Surrogate Molecule, mIL-17RA-Fc Decreases DiseaseIncidence and Progression in Mouse Collagen Induced Arthritis (CIA)Model A) Mouse Collagen Induced Arthritis (CIA) Model

The CIA model of arthritis is an appropriate and well-regarded model toevaluate therapeutic potential of drugs (such as IL-17RC and IL-17RA/RCproteins described herein) to treat human arthritis. In the CIA model,mRNA levels of murine IL-17A and IL-17F were found to be significantlyelevated (10-20 fold increases; p<0.001) in the affected popliteal lymphnodes and paws of arthritic mice compared to levels found in lymph nodesand paws of mice without arthritis, further supporting its use as amodel for diseases in which IL-17A and IL-17F play a role. ThemIL-17RA-Fc protein is an appropriate surrogate to the IL-17RC andIL-17RA/RC proteins described herein, since mIL-17RA-Fc can both andneutralize murine IL-17A and IL-17F, which is a similar feature of humanIL-17RC or IL-17RA/RC being able to bind human IL-17A and IL-17F.

Eight to ten-week old male DBA/1J mice (Jackson Labs; ˜25-30 g each)were used for these studies. On day-21, animals were given anintradermal tail injection of 100 uL of 1 mg/ml chick Type II collagenformulated in Complete Freund's Adjuvant (prepared by Chondrex, Redmond,Wash.), and three weeks later on Day 0 mice were given the sameinjection except prepared in Incomplete Freund's Adjuvant. Animals beganto show symptoms of arthritis following the second collagen injection,with most animals developing inflammation within 1-2 weeks. The extentof disease was evaluated in each paw by using a caliper to measure pawthickness, and by assigning a clinical score (0-3) to each paw:0=Normal, 0.5=Toe(s) inflamed, 1=Mild paw inflammation, 2=Moderate pawinflammation, and 3=Severe paw inflammation as detailed below.

B) Monitoring Disease

Incidence of disease in this model is typically 95-100%, and 0-2non-responders (determined after 6 weeks of observation) are typicallyseen in a study using 40 animals. Note that as inflammation begins, acommon transient occurrence of variable low-grade paw or toeinflammation can occur. For this reason, an animal is not considered tohave established disease until marked, persistent paw swelling hasdeveloped.

All animals were observed daily to assess the status of the disease intheir paws, which was done by assigning a qualitative clinical score toeach of the paws. Every day, each animal had its 4 paws scored accordingto its state of clinical disease. To determine the clinical score, thepaw is thought of as having 3 zones, the toes, the paw itself (manus orpes), and the wrist or ankle joint. The extent and severity of theinflammation relative to these zones was noted including: observation ofeach toe for swelling; torn nails or redness of toes; notation of anyevidence of edema or redness in any of the paws; notation of any loss offine anatomic demarcation of tendons or bones; evaluation of the wristor ankle for any edema or redness; and notation if the inflammationextends proximally up the leg. A paw score of 1, 2, or 3 was based firston the overall impression of severity, and second on how many zones areinvolved. The scale used for clinical scoring is shown below.

C) Clinical Score

-   -   0=Normal    -   0.5=One or more toes involved, but only the toes are inflamed    -   1=mild inflammation involving the paw (1 zone), and may include        a toe or toes    -   2=moderate inflammation in the paw and may include some of the        toes and/or the wrist/ankle (2 zones)    -   3=severe inflammation in the paw, wrist/ankle, and some or all        of the toes (3 zones)

Treatments:

Established disease was defined as a qualitative score of pawinflammation ranking 1 or more. Once established disease was present,the date was recorded, designated as that animal's first day with“established disease”, and treatment started. Mice were teated with PBS,or one of the following doses of mIL-17RA-Fc (diluted in PBS to desiredconcentration) i.p. every other day for a total of 5 doses: 150 μg; 75μg; 25 ug; 10 μg.

Blood was collected throughout the experimental period to monitor serumlevels of anti-collagen antibodies, as well as serum immunoglobulin andcytokine levels. Animals were euthanized 48 hours following their last(5^(th)) treatment, which was ˜11 days following disease onset. Bloodwas collected for serum, and all paws were collected into 10% NBF forhistology. Serum was collected and frozen at −80° C. for immunoglobulinand cytokine assays. The average paw scores for groups of mice treatedwith mIL-17RA-Fc are show below in Table 9.

TABLE 9 Average paw score for groups of mice treated with mIL-17RA-Fc inCIA model. Treatment Day 4 of treatment Day 10 of treatment PBS 1.59 +0.15  2.13 + 0.20   10 μg mIL-17RA-Fc 0.89 + 0.16* 1.49 + 0.14*  20 μgmIL-17RA-Fc 0.95 + 0.19* 1.35 + 0.24*  75 μg mIL-17RA-Fc 0.86 + 0.13*1.18 + 0.12* 150 μg mIL-17RA-Fc 0.64 + 0.17* 0.83 + 0.2*  Note: day 1was first day of therapeutic treatments; treatments were administeredevery other day via i.p. injections. Data are shown as mean + SEM.*average paw scores significantly different than PBS-treated group (p <0.05)

There was a dose-dependent, significant reduction in clinical scoreseverity of mice treated with mIL-17RA-Fc compared to PBS-treated mice.The mice treated with 10 ug mIL-17RA-Fc had the least amount ofsignificant efficacy (i.e., only significant for 3 out of the 10treatment days). When analyzed by repeated measures ANOVA, the trendover time was statistically different for mice treated with 10 and 25 ugmIL-17RA-Fc compared to PBS (p<0.05); trend over time for mice treatedwith 75 ug or 150 ug mIL-17RA-Fc was highly significant compared toPBS-treated mice (p<0.001). Mice treated with mIL-17RA-Fc also had adose-dependent reduction in the number of affected paws. For all serumcytokines measured at termination (IL-1β, -6, -10, -12, -15, -17, IP-10,GM-CSF, TNF-α, MIP-1α, MCP, KC, and RANTES), serum levels were increasedin diseased animals compared to non-diseased, pre-bled animals. WithmIL-17RA-Fc treatments, serum cytokine levels of IL-1β, -6, -10, -15,and MIP-1α were reduced compared to PBS-treated mice. The greatest andmost significant reductions were seen in 150 μg mIL-17RA-Fc treatedanimals. There was also a dose-dependent increase in the serum levels ofmIL-17RA-Fc, measured at the end of the experiment. Histologicalanalyses demonstrated dose-dependent reductions in joint inflammationand joint destruction, with groups of mice treated with 75 μgmIL-17RA-Fc showing significant reductions at p<0.01 and groups treatedwith 150 μg mIL-17RA-Fc showing the greatest efficacy (p<0.001).

All diseased animals showed higher levels of anti-collagen Ab by ELISAin the serum compared to prebled animals. No significant differenceswere seen between the treatment groups.

In summary, these results indicate that a murine surrogate (e.g.,mIL-17RA-Fc) of the human IL-17RC and IL-17RA/RC proteins describedherein can reduce inflammation, as well as disease incidence andprogression associated with this appropriate model of arthritis, thusindicating efficacy of human IL-17RC and IL-17RA/RC proteins for thetreatment of human arthritis.

Example 24 Stable Over-Expression of IL-17RC in the Murine Assay CellLine, Nih3t3/kz142.8 Expressing the ap1/nfkb Transcription Factor

The murine nih3t3/kz142.8 assay cell line was transfected with a humanIL-17RCx1 (SEQ ID NO:2) in an expression vector with a methotrexateresistance gene (dihydrofolate reductase, DHFR) This transfection wasperformed using a commercially available kit and the manufacturer'srecommendations. (Mirus, Madison, Wis. Cat. #MIR218) Cells were placedin 1 μM mtx amended growth medium to select for the expression vectorcontaining the human IL-17RCX1 transgene. After selection a humanIL-17RCx1 transfection pool was generated, and callednih3t3/kz142.8/hcytor14x1.

A) Luciferase assay using the nih3t3/kz142.8 assay cell line

Since nih3t3/kz142.8 has a stable kz142 reporter, there is no need foradenovirus infection to add this reporter. Thus the luciferase assayprotocol was shorted and done the following way:

1. Cell Plating

nih3t3/kz142.8 cells were plated at 5000 cells/well in solid white, cellculture coated 96 well plates, (Cat. #3917. Costar) using DMEM/10% FBS,containing glutamine and amended with pyruvate and cultured overnight at37° C. and 5% CO2. On this second day, the plating media was removed andexchanged for DMEM/1% FBS, containing glutamine and amended withpyruvate and cultured overnight at 37° C. and 5% CO2.

2. Luciferase assay measuring IL-17A and F activation of the stablekz142 reporter

Following the overnight incubation in the 1% FBS, DMEM media, humanIL-17A, and IL-17F ligand dilutions were made in serum free media,amended with BSA to a 0.28% level. After adding the ligand dilutions,cells were incubated at 37° C. and 5% CO₂ for 4 hours, after which themedia was removed, cells lysed for 15 minutes and mean fluorescenceintensity (MFI) measured using the luciferase assay system and reagents,(Cat.#e1531 Promega. Madison, Wis.) and a Microplate luminometer.Activity was detected for both ligands at concentrations ranging from0.1-1000 ng/ml. The nih3t3/kz142.8/hcytor14x1 transfection pool showedsimilar activity for the murine IL-17A ligand as did the parental cellline (Example 14). However, the cytor14x1 transfectant pool showed anelevated responsiveness to human IL-17A and F treatments, even whenthese ligand concentrations were as low as 20 femptograms. The fact thatthe mIL-17A signaling is comparable to that in the parental cell line(example 14) suggests that there isn't a general, non-specific problemwith human IL-17RC-expressing cells and that the murine IL-17A isprobably signaling through the endogenous murine nih3t3 cell IL-17R orIL-17RC receptor. Thus, the fact that human IL-17A and IL-17F cause anelevation of MFI at such low ligand concentrations may indicate aspecific hyper-responsiveness of the cells to those ligands, which ismediated through the over-expressed human IL-17RC receptor.

This result has significant clinical and biological ramifications andutility. For example, physiological situations could cause localup-regulation of the IL-17RC receptors which could then make these areashyper-responsive to IL-17A and IL-17F, resulting in biologicalactivation at much lower ligand concentrations than those suggestedwithout IL-17RC over-expression. Thus, far lower soluble receptor levelsmay be sufficient to antagonize these hypothetically lower ligandconcentrations, than previously thought or recognized by those in thefield.

Example 25 Antagonists to IL-17F and IL-17A Activity Decrease DiseaseIncidence and Progression in an Inflammatory Bowel Disease (IBD) Model

This model is designed to show that cultured intestinal tissue frompatients with IBD produce higher levels of inflammatory mediatorscompared to tissue from healthy controls. This enhanced production ofinflammatory mediators (including but not limited to IL-1β, IL-4, IL-5,IL-6, IL-8, IL-12, IL-13, IL-15, IL-17 A and F, IL-18, IL-23, TNF-α,IFN-γ, MIP family members, MCP-1, G- and GM-CSF, etc.) contributes tothe symptoms and pathology associated with IBDs such as Crohn's disease(CD) and ulcerative colitis (UC) by way of their effect(s) on activatinginflammatory pathways and downstream effector cells. These pathways andcomponents then lead to tissue and cell damage/destruction observed invivo. Therefore, this model can simulate this enhanced inflammatorymediator aspect of IBD. Furthermore, when intestinal tissue from healthycontrols or from human intestinal epithelial cell (IEC) lines iscultured in the presence of these inflammatory components, inflammatorypathway signaling can be observed, as well as evidence of tissue andcell damage.

Therapeutics that would be efficacious in human IBD in vivo would workin the above ex vivo or IEC models by inhibiting and/or neutralizing theproduction and/or presence of inflammatory mediators.

In this model, human intestinal tissue is collected from patients withIBD or from healthy controls undergoing intestinal biopsy, re-sectioningor from post-mortem tissue collection, and processed using amodification of Alexakis et al. (Gut 53:85-90; 2004). Under asepticconditions, samples are gently cleaned with copious amounts of PBS,followed by culturing of minced sections of tissue, in the presence ofcomplete tissue culture media (plus antibiotics to prevent bacterialovergrowth). Samples from the same pool of minced tissue are treatedwith one of the following: vehicle (PBS); recombinant human (rh) IL-17A;rhIL-17F; or rhIL-17A+rhIL-17F. In addition, these are treated with orwithout an antagonist of either IL-17A or IL-17F, alone or incombination (such as a soluble IL-17RC). This experimental protocol isfollowed for studies with human IEC lines, with the exception that cellsare passaged from existing stocks. After varying times in culture (from1 h to several days), supernatants are collected and analyzed for levelsof inflammatory mediators, including those listed above. In samples frompatients with IBD or in samples treated with rhIL-17A and/or F, levelsof inflammatory cytokines and chemokines are elevated compared tountreated healthy control tissue samples. The addition of antagonists toIL-17F and/or IL-17A activity, such as IL-17RC soluble receptors andantibodies thereto including the anti-human-IL-17RC monoclonal andneutralizing antibodies of the present invention markedly reduces theproduction of inflammatory mediators, and thus, would expect to beefficacious in human IBD.

Example 26 Antagonists to IL-17F and IL-17A activity Decrease DiseaseIncidence and Progression in a Multiple Sclerosis (MS) Model

Multiple sclerosis (MS) is a complex disease that is thought to bemediated by a number of factors, including the presence of lymphocyticand mononuclear cell inflammatory infiltrates and demyelinationthroughout the CNS. Microglia are macrophage-like cells that populatethe central nervous system (CNS) and become activated upon injury orinfection. Microglia have been implicated as playing critical roles invarious CNS diseases including MS, and may be used to study mechanism(s)of initiation, progression, and therapy of the disease (Nagai et al.Neurobiol Dis 8:1057-1068; 2001; Olson et al. J Neurosci Methods128:33-43; 2003). Immortalized human microglial cell lines and/orestablished human astroglia cell lines can, therefore, be used to studysome of the effects of inflammatory mediators on these cell types andtheir potential for neutralization. Inflammatory mediators (includingbut not limited to IL-1β, IL-6, IL-8, IL-12, IL-13, IL-15, IL-17 A andF, IL-18, IL-23, TNF-α, IFN-γ, MIP family members, RANTES, IP-10, MCP-1,G- and GM-CSF, etc.) can contribute to the symptoms and pathologyassociated with MS by way of their effect(s) on activating inflammatorypathways and downstream effector cells.

In order to evaluate the pro-inflammatory actions of IL-17A and IL-17F,and the ability of an antagonist to IL-17F and/or IL-17A activity, suchas IL-17RC soluble receptors and antibodies thereto including theanti-human-IL-17RC monoclonal and neutralizing antibodies of the presentinvention to neutralize or decrease these effects, cultured glial cellsare treated with one of the following: vehicle; rhIL-17A; rhIL-17F;rhIL-17A+IL-17F. In addition, these are treated with or without anantagonist of either IL-17A or IL-17F, alone or in combination (such asa soluble IL-17RC). After varying times in culture (from 1 h to severaldays), supernatants and cells are collected and analyzed for levelsand/or expression of inflammatory mediators, including those listedabove. Levels of inflammatory cytokines and chemokines are elevated inthe presence of rhIL-17A and/or IL-17F compared to cultures treated withvehicle alone. The addition of antagonists to IL-17F and/or IL-17Aactivity, such as IL-17RC soluble receptors and antibodies theretoincluding the anti-human-IL-17RC monoclonal and neutralizing antibodiesof the present invention markedly reduces the production and expressionof inflammatory mediators, and thus, would expect to be efficacious ininflammatory aspects associated with human MS.

Example 27 Antagonists to IL-17F and IL-17A activity Decrease DiseaseIncidence and Progression in a Rheumatoid Arthritis (RA) andOsteoarthritis (OA) Model

This model is designed to show that human synovial cultures (includingsynovial macrophages, synovial fibroblasts, and articular chondrocytes)and explants from patients with RA and OA produce higher levels ofinflammatory mediators compared to cultures/explants from healthycontrols. This enhanced production of inflammatory mediators (includingbut not limited to oncostatin M, IL-1β, IL-6, IL-8, IL-12, IL-15, IL-17

A and F, IL-18, IL-23, TNF-α, IFN-γ, IP-10, RANTES, RANKL, MIP familymembers, MCP-1, G- and GM-CSF, nitric oxide, etc.) contributes to thesymptoms and pathology associated with RA and OA by way of theireffect(s) on activating inflammatory pathways and downstream effectorcells. These pathways and components then lead to inflammatoryinfiltrates, cartilage and matrix loss/destruction, bone loss, andupregulation of prostaglandins and cyclooxygenases. Therefore, thismodel can simulate the destructive inflammatory aspects of RA and OA inin vitro and ex vivo experiments. Furthermore, when explants andsynovial cultures from healthy controls are cultured in the presence ofseveral of these inflammatory components (e.g. oncostatin M, TNF-α,IL-1β, IL-6, IL-17A and F, IL-15, etc.), inflammatory pathway signalingcan be observed. Therapeutics that would be efficacious in human RA invivo would work in the above in vitro and ex vivo models by inhibitingand/or neutralizing the production and/or presence of inflammatorymediators.

In this model, human synovial explants are collected from patients withRA, OA, or from healthy controls undergoing joint replacement or frompost-mortem tissue collection, and processed using a modification ofWooley and Tetlow (Arthritis Res 2: 65-70, 2000) and van 't H of et al(Rheumatology 39:1004-1008, 2000). Cultures of synovial fibroblasts,synovial macrophages and articular chondrocytes are also studied.Replicate samples are treated with one of the following: vehicle (PBS);recombinant human (rh) IL-17A; rhIL-17F; or rhIL-17A+rhIL-17F, and somesamples contain various combinations of oncostatin M, TNF-α, IL-1β,IL-6, IL-17A, IL-17F, and IL-15. In addition, these are treated with orwithout an antagonist to IL-17F and/or IL-17A activity, such as IL-17RCsoluble receptors and antibodies thereto including theanti-human-IL-17RC monoclonal and neutralizing antibodies of the presentinvention. After varying time of culture (from 1 h to several days),supernatants are collected and analyzed for levels of inflammatorymediators, including those listed above. In samples from patients withRA or OA, or in samples treated with rhIL-17A and/or F (either alone orin combination with other inflammatory cytokines), levels ofinflammatory cytokines and chemokines are elevated compared to untreatedhealthy control explants or in untreated cell cultures. The addition ofantagonists to IL-17F and/or IL-17A activity, such as IL-17RC solublereceptors and antibodies thereto including the anti-human-IL-17RCmonoclonal and neutralizing antibodies of the present invention markedlyreduces the production of inflammatory mediators, and thus, would expectto be efficacious in human RA and OA.

Example 28 IL-17A and IL-17F Functional Responses

NIH-3T3/KZ142 cells were stably transfected with human IL-17RCx1 (SEQ IDNO:1) and mouse IL-17RCx1 (SEQ ID NO:25). As described above, each linewas treated for 7 and 15 minutes with a dose response of IL-17A, IL-17F,murine IL-17F, and appropriate controls. Both IL-17A and IL-17F gave adose dependent response in phosphorylated IκB-α and p38 MAPKtranscription factors when IL-17RCx1 (SEQ ID NO:1) was transfected,approximately 30% greater then the inherent signaling from the controlline. IL-17A and IL-17F gave no increase in signaling when the murimeIL-17RCx1 (SEQ ID NO:25) was transfected. Murine IL-17F gave no increasein signaling for either human or murine IL-17RCx1.

Example 29 IL-17A, IL-17F, IL-17RA and IL-17RC Expression in MurineDisease Models

Four murine models of disease (asthma, DSS colitis, atopic dermatitisand experimental allergic encephalomyelitis) were analyzed using knowtechniques for the expression of IL-17A, IL-17F, IL-17R and IL-17RC.

In the asthma model, IL-17A and IL-17F are expressed at very low toundetectable levels in lung, spleen, lung draining lymph nodes and lunginfiltrating cells in diseased and non-diseased mice. IL-17RC messagewas found to be more highly expressed in lung compared to spleen andlymph node but was not regulated with disease. IL-17R was more highlyexpressed in spleen and lung draining lymph node compared to lung butwas also not regulated with disease.

Contrary to the asthma model, IL-17A and IL-17F were highly up-regulatedin diseased but not normal mice in the DSS-colitis model in bothproximal and distal colon. Neither cytokine was significantlyup-regulated in the mesenteric lymph node. Further, it was found thatup-regulation of both cytokines in the context of acute DSS-inducedcolitis and not in chronic DSS-induced colitis. IL-17R was found to beprominently expressed in mesenteric lymph nodes as compared to proximaland distal colon, but was not regulated with disease. In contrast,IL-17RC was more highly expressed in proximal distal colon tissuecompared to mesenteric lymph nodes. IL-17RC expression was also notregulated with disease.

In atopic dermatitis, IL-17A mRNA was not detectable. IL-17F was foundto be expressed in both skin and skin-draining lymph nodes but did notappear to be significantly regulated with disease. IL-17R mRNA was morehighly expressed in skin-draining lymph nodes as compared to skin butwas not regulated with disease. IL-17RC was more highly expressed inskin compared to skin-draining lymph nodes but was also not regulatedwith disease.

In experimental allergic encephalomyelitis, both IL-17A and IL-17Fappeared to up-regulated in spinal chord in diseased but not healthymice. IL-17F may have been more highly expressed in lymph nodes comparedto spinal cord but expression in the lymph nodes was not regulated withdisease. However, overall levels of expression in these tissues wasquite low. IL-17R was more highly expressed in lymph node tissuecompared to brain and spinal cord. IL-17RC was not tested.

In short, IL-17A and IL-17F expression appears to be regulated withdisease in the context of the DSS-induced colitis and experimentalallergic encephalomyelitis models but apparently not for asthma oratopic dermatitis. IL-17R and IL-17RC expression does not appear to beregulated with disease but IL-17R expression appears to be enriched inlymphoid tissues while IL-17RC expression appears to be enriched innon-lymphoid tissues.

Example 30 IL-17RC is a Mediator of Activation to Both IL-17A and IL-17F

The murine nih3t3/kz142.8 assay cell line was transfected with a humanIL-17RCX1 (SEQ ID NO:2) in an expression vector with a methotrexateresistance gene. (dihydrofolate reductase, DHFR) Human IL-17RA (SEQ IDNO:21) was similarly tranfected into this cell line. Transfections wereperformed using a commercially available kit and the manufacturer'srecommendations. (Mirus, Madison, Wis. Cat. #MIR218) Cells were placedin 1 μM mtx amended growth medium to select for the expression vectorcontaining the expression constructs. After selection transfection poolswere generated, and called nih3t3/kz142.8/hcytor14x1 andnih3t3/kz142.8/IL-17R.

A) Luciferase Assay Using the nih3t3/kz142.8-Based Cell Lines.

Since nih3t3/kz142.8 based cell lines have stable ap1/nfkb reporters(kz142), there is no need for adenovirus infection to add this reporter.Thus the luciferase assay protocol was shorted and done the followingway:

1. Cell Plating

Cells were plated at 5000 cells/well in solid white, cell culture coated96 well plates, (Cat. #3917. Costar) using DMEM/10% FBS, containingglutamine and amended with pyruvate and cultured overnight at 37° C. and5% CO₂. On this second day, the plating media was removed and exchangedfor DMEM/1% FBS, containing glutamine and amended with pyruvate andcultured overnight at 37° C. and 5% CO₂.

2. Luciferase Assay Measuring IL-17A and F Activation of the Stablekz142 Reporter

Following the overnight incubation in the 1% fbs, DMEM media, humanIL-17A, and IL-17F ligand dilutions were made in serum free media,amended with BSA to a 0.28% level. After adding the ligand dilutions,cells were incubated at 37° C. and 5% CO₂ for 4 hours, after which themedia was removed, cells lysed for 15 minutes and mean fluorescenceintensity (MFI) measured using the luciferase assay system and reagents,(Cat.#e1531 Promega. Madison, Wis.) and a Microplate luminometer.Activity was detected for both ligands at concentrations ranging from0.1-100 ng/ml.

The EC50s discussed below are averages of at least 4 experiments. Thenih3t3/kz142.8/hcytor14x1 transfection pool showed similar activity forthe murine IL-17A ligand as did the parental cell line, with an EC50 ofabout 4 ng/ml (Example 14). The fact that the mIL-17A signaling in thehcytor14x1 recombinant line is comparable to that in the parental cellline (example 14) suggests that murine IL-17A is probably signalingthrough the endogenous murine nih3t3 cell IL-17RA or IL-17RC receptorsand does not activate the cells through hcytor14x1. However, thehIL-17RCX1 transfectant pool showed an elevated responsiveness to humanIL-17A treatment, with an EC50 of 0.41 ng/ml Vs 2.8 ng/ml (averages of 4experiments) in the parental line (a 6.8 fold more potent EC50 in therecombinant line) In addition, the hIL-17RCX1 recombinant line had anenhanced responsiveness to hIL-17F, with an EC50 of 0.61 ng/ml in therecombinant line Vs 10 ng/ml in the parental line (a 17-fold more potentEC50 in the recombinant line). The increased potency to hIL-17A and F inthe hIL-17RCX1 line is consistent with human IL-17RCX1 being a highaffinity receptor for both human IL-17A and IL-17F. In contrast, thehIL-17RA recombinant line had enhanced sensitivity only to hIL-17A, withan EC50 of 0.6 ng/ml vs 2.8 ng/ml for the parental line. There was notan enhancement of the hIL-17F EC50 in the hIL-17RA recombinant line,with an IL-17F EC50 of 12.4 ng/ml vs 8.9 ng/ml in the parental line.

This result is significant because it specifically implicates hIL-17RCX1as a mediator of activation to both hIL-17A and hIL-17F and suggeststhat hIL-17RA mediates signaling only to hIL-17A activation and nothIL-17F.

Example 31 Intravenous Administration of IL-17A and IL-17F

To determine the effect of i.v. delivery of murine or human IL-17A orIL-17F on complete blood counts (CBC) and serum cytokines/chemokines inBALB/c mice at various time points.

I.V. administration of 1 μg mIL-17A resulted in an approximate 2-foldincrease in circulating neutrophils (by CBC) and approximate 10-foldincrease in serum KC and MCP-1 (by Luminex) 1-2 h followingadministration; similar results in these chemokines were observed with 5ug hIL-17A. Blood monocyte levels were also significantly increased inmice treated with 1 μg mIL-17A (showed the greatest increase), 5 μghIL-17A or 5 μg hIL-17F at the 2 h timepoint. I.V. administration of mand hIL-17F resulted in marked increases in serum IL-15 (by Luminex) atthe 1 and 2 h time points, and small increases in serum KC and MCP-1 atthese same timepoints.

Example 32 Neutralization of Intravenous Administration IL-17A andIL-17F

To neutralize the i.v. IL-17A and IL-17F-mediated increases in cytokinesand chemokines with i.p. soluble receptors (mIL-17RA:Fc for murineligands; soluble human IL-17RC for human ligands), female BALB/c micewere administered by i.p. injection either PBS, 100 μg mIL-17RA-Fc, or100 μg soluble human IL-17RC three hours prior to receiving by i.v. tailinjection: PBS; 2 μg of either mIL-17A, mIL-17F, or 2 μg of both mIL-17Aand mIL-17F (for mice that received mIL-17RA-Fc); or 2 μg of eitherhIL-17A, hIL-17F, or 2 μg of both hIL-17A and hIL-17F (for mice thatreceived soluble human IL-17RC). Serum was collected 1 h followingligand administration and analyzed for a small number of serum cytokinesand chemokines.

Mice pretreated with i.p. murine soluble receptor had significantreductions (˜2-2.2 fold lower; p<0.05) in murine IL-17A-mediatedincreases in serum concentrations of IL-17A and KC (CXCL1) compared tomice treated with PBS+ murine IL-17A. Mice pretreated with i.p. humanIL-17RC-Fc had significant reductions (˜2-fold lower; p<0.05) in humanIL-17F-mediated increases in serum concentrations of IL-15; hadsignificant reductions (˜30% lower; p<0.05) in IL-17A-mediated increasesin KC; had significant reductions (˜25% lower; p<0.05) in humanIL-17A+IL-17F-mediated increases in KC; and had significant reductions(˜2-fold; p<0.05) in either human IL-17F or IL-17A+IL-17F mediatedincreases in IL-15.

Example 33 Plate Based Protein binding Assays of the Soluble IL-17RC andIL-17RC/IL-17RA Polypeptides

The format of the Capture EIA is as follows: Coat the ELISA plate withGoat anti Human IgG at 1 μg/ml and incubate overnight at 4° C. Wash andblock the plate with 200 μl per well 1% BSA for 1 hour at roomtemperature. Wash, add the soluble receptor variants (A1586F, A1587F) orIL17RCx1 (A1034F) dilution series (100 μg/ml through 0.10 μg/ml) to theplate and incubate for 1 hour at room temperature. Wash, add biotinlabeled ligand @ 10:1 (IL17A) or 6:1 (IL17F) and incubate for 1 hour atroom temperature. Wash, add Strept Avidin-Horse Radish Peroxidase @ 0.5μg/mL and incubate for 1 hour at room temperature. Wash, add TMBsubstrate for 4 minutes. Stop the reaction by adding Stop Solution.(Note: All reagents volumes were 50 μl per well unless statedotherwise). A positive result would be high OD values, generally above0.5. The results indicated that construct 1342 (SEQ ID NO:74) does notbind IL-17A and weakly binds IL-17F in this assay. Construct 1341 (SEQID NO:72) binds both IL-17A and IL-17F very strongly. IL-17RCx1 bindsIL-17A and IL-17F.

The format of the Neutralization EIA is as follows: Coat the ELISA platewith soluble receptor (A1034F) at 1 μg/ml and incubate overnight at 4°C. Wash and block the plate with 200 μl per well 1% BSA for 1 hour atroom temperature. While blocking, in a separate plate incubate thesoluble receptor variants (A1586F, A1587F) dilution series (50 μg/mlthrough 0.05 μg/ml) with biotin labeled ligand @ 10:1 (IL17A) or 6:1(IL17F) in equal volumes for 1 hour at room temperature. Wash theblocked plate, add the receptor-ligand complex to the blocked plate andincubate for 1 hour at room temperature. Wash, add Strept Avidin-HorseRadish Peroxidase @ 0.5 μg/mL and incubate for 1 hour at roomtemperature. Wash, add TMB substrate for 7 minutes. Stop the reaction byadding Stop Solution. (Note: All reagents volumes were 50 μl per wellunless stated otherwise). A positive result would be low OD values,generally below 0.5. The results indicated that construct 1342 (SEQ IDNO:74) weakly neutralizes binding of IL17A to IL17RCx1 and stronglyneutralizes binding of IL17F to IL17RCx1. Construct 1341 (SEQ ID NO:72)weakly neutralizes binding of IL17A to IL17RCx1 and weakly neutralizesbinding of IL17F to IL17RCx1. Neutralization indicates that the variantprotein is binding the biotinylated ligand.

Example 34 FACS Binding Assay Protocol

To assess the ability of the soluble IL-17RC and IL-17RC/IL-17RApolypeptides of the present invention to bind the ligands IL-17A andIL-17F, a Flow Cytometry-based competitive binding assay was utilized.Incubation of a BHK cell line stably transfected with full lengthIL17RCx4 in the presence of the ligands IL17A or IL17F, and the solublereceptor targeted to bind the ligands allows for detection and relativequantification of ligand bound to the cell surface (and thereforeunbound by the soluble receptor). The biotinylation of the ligand allowsfor FACS detection using a secondary Streptavidin conjugatedfluorophore. A reduction in cell bound ligand over a titration of thesoluble receptor is recorded as a reduction in the mean fluorescence ofthe cells. Biotinylated ligands are individually pre-mixed at 1 ug/mlwith titrating amounts of soluble receptor in staining media (HBSS+1%BSA+0.1% NaAzide+10 mM HEPES) in 100 ul volumes and incubated at RT for15 minutes. A BHK cell line stably transfected with full length IL17RCx4is prepared for ligand staining by resuspension with Versene (Invitrogencat.15040-066), equilibrating to 2×10e5 cells/100 ul, pelleting, andresuspension in the ligand/soluble receptor pre-mix. Stained cells areincubated at 4° for 30 minutes, washed 1× in staining media, and stainedwith Streptavidin-PE (BD Pharmingen cat. 554061) at a 1:100 ratio. Cellsare incubated at 4° in the dark for 30 minutes, washed 2× in stainingmedia, and re-suspended in a 1:1 ratio of staining media and Cytofix (BDBioscience 554655). The BD LSRII Flow Cytometer or similar instrument isused for data collection and analysis. FIG. 5 depicts a standard graph.The graph was generated using the Prizm software program. The Y valuesrepresent the MFI normalized to maximum and minimum (100% and 0%) basedon ligand only and no ligand/no soluble receptor control wells, and thusthe percent binding of the ligand to the cells. The software calculatesthe IC50 for each curve.

Example 35 Inhibition of Specific Binding of Biotinylated Human IL-17Aand IL17F with a Soluble IL-17RC/IL-17RA Polypeptide

The binding assay used to determine the ability of the soluble IL-17RCand IL-17RC/IL-17RA polypeptides to bind IL-17A and IL17F is describedherein. Binding studies are performed as discussed above, except thatadditional soluble polypeptides, such as SEQ ID NOs: 157 and 158 wasincluded in the binding reaction. This soluble polypeptide inhibitedbinding of both human IL-17A and IL-17F to IL-17RC transfected BHK cellsto the same extent as soluble human IL-17RCx1 Fc fusion protein (SEQ IDNO:64). The remainder of soluble polypeptides, including the solublepolypeptide of SEQ ID Nos: 157 and 158, are included in Table 10 below.

TABLE 10* Soluble IC50- Soluble IC50- Polypeptide Variant IL17APolypeptide Variant IL17F IL17RA/RC 1407 7 IL17RC 1390 9 IL17RA/RC 14079 IL17RA/RC 1454 18 IL17RA/RC 1454 4 IL17RA/RC 1454 31 IL17RA/RC 1454 17IL17RA/RC 1454 95 IL17RA/RC 1454 20 IL17RA/RC 1407 33 IL17RC 1390 12IL17RA/RC 1407 42 IL17RA/RC 1341 30 IL17RC 1210 31 IL17RC 1210 35 IL17RC1210 61 IL17RC 1210 47 IL17RC 1210 67 IL17RC 1210 74 IL17RA/RC 1341 47IL17RC 1459 126 IL17RC 1459 103 IL17RC 1342 217 IL17RC 1342 313*Cell-based Competition Binding IC50 (ng/uL); ordering of Constructsfrom strongest binders to weakest based on IC50's for each ligand

Example 36 Binding Affinity of the IL-17RC and IL-17RC/IL-17RA SolublePolypeptides to IL-17A and IL-17F

IL-17RCx1, IL-17RA and the soluble IL-17RC/IL-17RA soluble polypeptide(SEQ ID Nos: 157 and 158) were tested for binding affinity to bothIL-17A and IL-17F as follows: Gt-anti-Hu IgG-Fc specific Antibody(Jackson #109-005-008) was diluted to 50 ug/ml in pH 5.0 Na Acetate andimmobilized onto a CM5 Biacore chip. The protocol was optimized tocapture receptor at a theoretical binding max. before injecting aconcentration series of each ligand to observe association anddissociation. The soluble receptors and the IL-17RC/IL-17RA polypeptidewere tested for binding of a concentration series of each ligand. Thesurface was regenerated with 2×30 sec. injections of pH 1.75 glycinebetween cycles. Data was evaluated using Biacore Evaluation software todefine kinetic values and is shown in Table 11 below.

TABLE 11* ka (1/Ms) kd (1/s) KD (M) Rmax (RU) Chi² (RU²) Human IL17RCx1Affinity for Human IL-17A May 2005 1.05E+06 4.90E−04 4.69E−10 9.02 0.4241.24E+06 4.38E−04 3.52E−10 8.86 0.324 Human IL17RCx1 Affinity for HumanIL-17F May 2005 9.91E+05 4.31E−04 4.35E−10 7.22 0.378 1.11E+06 3.84E−043.46E−10 7.57 0.549 Soluble IL-17RC/IL-17RA Polypeptide for Human IL-17AApril 2006 1.42E+06 6.22E−05 4.39E−11 20.5 0.460 2.61E+06 9.95E−053.82E−11 18.3 0.888 Soluble IL-17RC/IL-17RA Polypeptide for Human IL-17FApril 2006 1.82E+06 2.61E−04 1.43E−10 10.2 0.495 2.49E+06 3.15E−041.26E−10 11.2 0.544 Human IL-17RA Affinity for Human IL-17A June 20063.70E+05 8.65E−05 2.34E−10 29.5 0.249 2.89E+05 8.57E−05 2.96E−10 35.10.197 Human IL-17RA Affinity for Human IL-17F July 2006 2.09E+045.56E−04 2.66E−08 20.3 0.071 2.55E+04 4.40E−04 1.72E−08 9.9 0.076*Equilibrium and rate constants are shown and values fall within machinelimits. Chi2 refers to the sum of the square of the residuals betweenthe binding curves and the evaluation fitting curves. The closer to 0,the more confidence we have in the data. This data is shown with goodconfidence.

These data demonstrates the binding of human IL-17A and human IL-17F tohuman IL-17RA and human IL-17RC. Specifically, human IL-17RCdemonstrates similar binding affinity for both human IL-17A and humanIL-17F with dissociation equilibrium constants (KD) in the 400 picomolar(pM) range. The soluble IL-17RC/IL-17RA polypeptide bound human IL-17Awith slightly higher affinity, KD˜40 pM, than human IL-17F, KD˜140 pM.Human IL-17RA produced the largest discrepancy of ligand affinity with a100-fold difference between human IL-17A, KD˜300 pM, and human IL-17F,KD˜30 nanomolar (nM), binding.

Example 37 Creation of Recombinant Human IL-17RA/NIH3T3/KZ142.8 andIL-17RCx4/NIH3T3/KZ142.8 Reporter Assay Cell Lines

The murine NIH3T3/KZ142.8 reporter cell line described herein was usedto create new assay cell lines, recombinant for either human IL-17RA(SEQ ID NO:21) or IL-17RCx4 (SEQ ID NO:166). This was accomplished bytransfection of these cells with expression constructions containingeach of these cDNAs. The expression vector utilized, pzmp11, whichcontains the dihydrofolate reductase gene. Thus transfectants wereselected using 1 uM methotrexate amended growth medium to create stablepools. These assay cell lines were called hIL-17RA/NIH3T3/KZ142.8 andhIL-17RCX4/NIH3T3/KZ142.8.

Example 38 A Soluble IL-17RC/IL-17RA Polypeptide Antagonizes HumanIL-17A Activation of Recombinant Human IL-17RA/NIH3T3/KZ142.8 Cells

The efficacy of soluble IL-17RC/IL-17RA soluble polypeptide (SEQ ID Nos:157 and 158) competition for human IL-17A activation of recombinanthIL-17RA/NIH3T3/KZ142.8 cells was measured as follows: Cell plating andpreparation for a luciferase assay was the same as that describedherein. The day of the assay, these cells were first given a triplicate2 fold dose series of one volume of soluble receptors at 2 fold thefinal concentration including the soluble polypeptide above, IL-17RA andIL-17RC beginning at a 2 μg/ml, (which results in a 1 ug/ml finalconcentration once combined with the ligand). Next one volume of IL-17Awas applied at 1 ng/ml, which is 2 fold the final concentration of 0.5ng/ml which results from the receptor-ligands mixing together. Themaximum activation was determined using a triplicate set which received0.5 ng/ml of IL-17A without receptor. The basal activation wasdetermined using a triplicate set which received only assay medium whichcontained neither ligand nor soluble receptor. Data analysis revealedIC50 for IL-17A activation of the above cell line by the solublepolypeptide was 1 ng/ml. There wasn't sufficient potency of solubleIL-17RA or IL-17RC to convincingly antagonize 0.5 ng/ml hIL-17Aactivation of this cell line with even the highest dose of 1 μg/mlsoluble receptor.

Example 39 A Soluble IL-17RC/IL-17RA Polypeptide Antagonizes HumanIL-17F Activation of Recombinant Human IL-17RA/NIH3T3/KZ142.8 cells

The efficacy of the soluble IL-17RC/IL-17RA polypeptide (SEQ ID Nos: 157and 158) competition for human IL-17F activation of recombinanthIL-17RA/NIH3T3/KZ142.8 cells (described above) was measured as follows:Cell plating and preparation for a luciferase assay was the same as thatdescribed herein. The day of the assay, these cells were first given atriplicate 2 fold dose series of one volume of soluble polypeptide at 2fold the final concentration including the soluble polypeptide above,IL-17RA and IL-17RC beginning at a 4 ug/ml, (which results in a 2 ug/mlfinal concentration once combined with the ligand). Next one volume ofIL-17F was applied at 40 ng/ml, which is 2 fold the final concentrationof 20 ng/ml which results from the receptor-ligands mixing together. Themaximum activation was determined using a triplicate set which received20 ng/ml of IL-17F without receptor. The basal activation was determinedusing a triplicate set which received only assay medium which containedneither ligand nor soluble receptor. Data analysis revealed IC50 forIL-17F activation of the above cell line by the IL-17RC/IL-17RA solublepolypeptide of 0.48 ug/ml. There wasn't sufficient potency of solubleIL-17RA or IL-17RC to show any antagonism of 20 ng/ml IL-17F activationof this cell line with even the highest dose of 2 ug/ml solublereceptor.

Example 40 A Soluble IL-17RC/IL-17RA Polypeptide Antagonizes HumanIL-17F Activation of Recombinant Human IL-17RCx4/NIH3T3/KZ142.8 cells

The efficacy of soluble IL-17RC/IL-17RA polypeptide (SEQ ID Nos: 157 and158) competition for IL-17F activation of recombinanthIL-17RCX4/NIH3T3/KZ142.8 cells (described above) was measured asfollows: Cell plating and preparation for a luciferase assay was thesame as that described herein. The day of the assay, these cells werefirst given triplicate 5 fold serial doses of one volume of solublereceptors at 2 fold the final concentration including the above solublepolypeptide, IL-17RA and IL-17RC beginning at a 4 ug/ml. Next one volumeof IL-17F lot A1275F was applied at 2 ng/ml, which is 2 fold the finalconcentration of 1 ng/ml which results from the receptor-ligands mixingtogether. The maximum activation was determined using a triplicate setwhich received 1 ng/ml of IL-17F without receptor. The basal activationwas determined using a triplicate set which received only assay mediumwhich contained neither ligand nor soluble receptor. Data analysisrevealed IC50 for IL-17F activation of the soluble IL-17RC/IL-17RApolypeptide of 0.8 ug/ml, IL-17RC was bug/ml, and IL-17RA had noantagonism at any dose.

Example 41 Soluble IL-17RC/IL-17RA Polypeptide Neutralizes the Activityof Both Human IL-17A and IL-17F Induction of G-CSF, IL-6 and IL-8

Human small airway epithelial cells (SAEC) were treated with humanIL-17A or with human IL-17F and 48 hr supernatants were collected. Thesesupernatants were assayed and showed a dose-dependent induction ofG-CSF, IL-6, and IL-8, as shown in Table 12 below:

TABLE 12 Fold Induction in 48 hr supernatants SAEC treated with: G-CSFIL-6 IL-8 huIL-17A  50 ng/ml 26 13 8  10 ng/ml 24 14 6  2 ng/ml 14 8 3 0.4 ng/ml 13 8 3 huIL-17F 250 ng/ml 15 11 4  50 ng/ml 10 8 3  10 ng/ml8 8 2  2 ng/ml 4 5 2

SAEC were also treated with 0.01-10 ug/ml doses of solubleIL-17RC/IL-17RA polypeptide (SEQ ID Nos: 157 and 158) in combinationwith 10 ng/ml human IL-17A or 50 ng/ml human IL-17F (both ligand andsoluble polypeptide were incubated together for 30 minutes at 37° C.before adding to cells), and 48 hr supernatants collected. As shown inTable 13 below, these supernatants showed decreased G-CSF, IL-6, andIL-8, demonstrating that the soluble IL-17RC/IL-17RA polypeptide wasable to effectively neutralize the activity of both human IL-17A andhuman IL-17F induction of these cytokines. It is noted that IC50 valueswere not able to be determined for the neutralization of IL-6, becauseat the lowest dose (0.01 μg/ml) of the soluble IL-17RC/IL-17RApolypeptide tested, neutralization had only returned to approximately50% of max.).

TABLE 13 Soluble IL-17RA/RC receptor IC50 of IL-17RA/RC neutralizesactivity of huIL-17A/F: (ug/ml) huIL-17A(10 ng/ml) induction of G- 0.14CSF huIL-17F(50 ng/ml) induction of G- 1.20 CSF huIL-17A(10 ng/ml)induction of IL-8 0.03 huIL-17F(50 ng/ml) induction of IL-8 0.57huIL-17A(10 ng/ml) induction of IL-6 94% neutralized at 10 ug/ml 49%neutralized at 0.01 ug/ml huIL-17F(50 ng/ml) induction of IL-6 72%neutralized at 10 ug/ml 57% neutralized at 0.01 ug/ml

Example 42 Efficacy of the Soluble IL-17RC and IL-17RC/IL-17RAPolypeptides in Human Multiple Sclerosis Samples

Multiple sclerosis (MS) is a complex disease that is thought to bemediated by a number of factors, including the presence of lymphocyticand mononuclear cell inflammatory infiltrates and demyelinationthroughout the CNS. Microglia are macrophage-like cells that populatethe central nervous system (CNS) and become activated upon injury orinfection. Microglia and neuronal cells have both been implicated asplaying critical roles in various CNS diseases including MS, and may beused to study mechanism(s) of initiation, progression, and therapy ofthe disease (Nagai et al., Neurobiol Dis 8:1057-1068; 2001; Olson etal., J Neurosci Methods 128:33-43; 2003; Giuliani et al., J Neuroimmunol165: 83-91; 2005). Primary neuronal cell cultures, immortalized humanmicroglial cell lines and/or established human astroglia cell lines can,therefore, be used to study some of the effects of inflammatorymediators on these cell types and their potential for neutralization.Inflammatory mediators (including but not limited to IL-1β, IL-6, IL-8,IL-12, IL-13, IL-15, IL-17 A and F, IL-18, IL-23, TNF-α, IFN-γ, MIPfamily members, RANTES, IP-10, MCP-1, G- and GM-CSF, etc.) cancontribute to the symptoms and pathology associated with MS by way oftheir effect(s) on activating inflammatory pathways and downstreameffector cells.

In order to evaluate the pro-inflammatory actions of IL-17A and IL-17Fon these cells types, and the ability of the soluble polypeptides of thepresent invention, such as the soluble IL-17RC/IL-17RA polypeptide (SEQID NO:158) to neutralize or decrease these effects, cultured neuronal orglial cells are treated with one of the following: vehicle; rhIL-17A;rhIL-17F; rhIL-17A+IL-17F. In addition, these are treated with orwithout a soluble polypeptide of the present invention, such as thesoluble IL-17RC/IL-17RA polypeptide (SEQ ID NO:158). In a separate setof cultures, circulating T cells isolated from human subjects andactivated with anti-CD3, are added to the cultured neuronal and glialcells in the absence of exogenous IL-17A or IL17-F, thus providing aco-culture method of investigating the destructive effects of activatedT cells on these cell types. The T cells are treated with or without asoluble polypeptide of the present invention, such as the solubleIL-17RC/IL-17RA polypeptide (SEQ ID NO:158). After varying times inculture (from 1 h to several days), supernatants and cells are collectedand analyzed for levels and/or expression of inflammatory mediators,including those listed above, and also analyzed for cell survival.Levels of inflammatory cytokines and chemokines, and death of neuronalcells, are elevated in the presence of rhIL-17A and/or IL-17F comparedto cultures treated with vehicle alone. The addition of a solublepolypeptide of the present invention, such as the solubleIL-17RC/IL-17RA polypeptide (SEQ ID NO:158) markedly reduces theproduction and expression of inflammatory mediators in these cultures,and increases cell survival in the neuronal cells.

Therefore, because these ex vivo experiments demonstrate that a solublepolypeptide of the present invention, such as the solubleIL-17RC/IL-17RA polypeptide (SEQ ID NO:158) can reduce the destructiveand inflammatory actions that are associated with the pathobiology ofhuman MS, treatment with such soluble polypeptides would be expected tobe efficacious in reducing the inflammatory aspects, neuronal death,and/or demyelination associated with human MS.

Example 43 Efficacy of the Soluble IL-17RC and IL-17RC/IL-17RAPolypeptides in Human Rheumatoid Arthritis (“RA”) and Osteoarthritis(“OA”) Samples

These models are designed to show that human synovial cultures(including synovial macrophages, synovial fibroblasts, and articularchondrocytes) and explants from patients with RA and OA produce higherlevels of inflammatory mediators compared to cultures/explants fromhealthy controls, which in turn can contribute to the degradation ofextracellular matrix components (e.g. bone, cartilage, etc), which is ahallmark of these diseases. In addition, the co-culture models describedbelow are designed to show that inflammatory mediators present in RA/OAsynovial fluid and/or activated T cells can also result in greaterinflammation and matrix degradation.

The enhanced production of inflammatory mediators (including but notlimited to oncostatin M, IL-1β, IL-6, IL-8, IL-12, IL-15, IL-17 A and F,IL-18, IL-23, TNF-α, IFN-γ, IP-10, RANTES, RANKL, MIP family members,MCP-1, MMP-9, G- and GM-CSF, nitric oxide, etc.) contributes to thesymptoms and pathology associated with RA and OA by way of theireffect(s) on activating inflammatory pathways and downstream effectorcells. These pathways and components then lead to inflammatoryinfiltrates, cartilage and matrix loss/destruction, bone loss, andupregulation of matrix metalloproteases, prostaglandins andcyclooxygenases. Therefore, these models can simulate the destructiveinflammatory aspects of RA and OA in in vitro and ex vivo experiments.Furthermore, when explants and synovial cultures from healthy controlsare cultured in the presence of exogenously added inflammatorycomponents (e.g. oncostatin M, TNF-α, IL-1β, IL-6, IL-17A and F, IL-15,etc.), or alternatively, in the presence of synovial fluid from RApatients (which would contain inflammatory components endogenously),inflammatory and degradative pathway signaling can be observed.Therapeutics that would be efficacious in human RA in vivo would work inthe above in vitro and ex vivo models by inhibiting and/or neutralizingthe production and/or presence of inflammatory mediators.

In these models, human synovial explants are collected from patientswith RA, OA, or from healthy controls undergoing joint replacement orfrom post-mortem tissue collection, and processed using a modificationof Wooley and Tetlow (Arthritis Res 2: 65-70; 2000) and van 't H of etal (Rheumatology 39:1004-1008; 2000). Cultures of synovial fibroblasts,synovial macrophages and articular chondrocytes are also studied.Replicate samples are treated with one of the following: vehicle (PBS);recombinant human (rh) IL-17A; rhIL-17F; or rhIL-17A+rhIL-17F, and somesamples contain various combinations of oncostatin M, TNF-α, IL-1β,IL-6, IL-17A, IL-17F, and IL-15. A separate set of samples are treatedwith activated human T cells, or synovial fluid from healthy controls orpatients with RA or OA. In addition, all of these samples are treatedwith or without a soluble polypeptide of the present invention, such asa soluble IL-17RC polypeptide or a soluble IL-17RC/IL-17RA polypeptide(SEQ ID NO:158). After varying time of culture (from 1 h to severaldays), supernatants and cells are collected and analyzed for levels ofinflammatory mediators and cartilage/bone/matrix biomarkers, includingthose listed above. In samples from patients with RA or OA, or insamples treated with RA/OA synovial fluid, activated T cells, rhIL-17Aand/or rhIL-17F (either alone or in combination with other inflammatorycytokines), levels of inflammatory cytokines and chemokines andcartilage/bone/matrix degradative markers are elevated compared tountreated healthy control explants or in untreated cell cultures. Theaddition of a soluble polypeptide of the present invention markedlyreduces the production of inflammatory and cartilage/bone/matrixdegradative mediators, and thus, would expect to be efficacious in humanRA and OA.

Example 44 Efficacy of the Soluble IL-17RC and IL-17RC/IL-17RAPolypeptides in Human Inflammatory Bowel Disease (“IBD”) Samples viaMucosal Biopsy Cultures

This model is designed to show that cultured intestinal tissue frompatients with IBD produce higher levels of inflammatory mediatorscompared to tissue from healthy controls. This enhanced production ofinflammatory mediators (including but not limited to IL-1β, IL-4, IL-5,IL-6, IL-8, IL-12, IL-13, IL-15, IL-17 A and F, IL-18, IL-23, TNF-α,IFN-γ, MIP family members, MCP-1, G- and GM-CSF, etc.) contributes tothe symptoms and pathology associated with IBD such as Crohn's disease(CD) and ulcerative colitis (UC) by way of their effect(s) on activatinginflammatory pathways and downstream effector cells. These pathways andcomponents then lead to tissue and cell damage/destruction observed invivo. Therefore, this model can simulate this enhanced inflammatorymediator aspect of IBD. Furthermore, when intestinal tissue from healthycontrols or from human intestinal epithelial cell (IEC) lines iscultured in the presence of these inflammatory components, inflammatorypathway signaling can be observed, as well as evidence of tissue andcell damage.

Therapeutics that would be efficacious in human IBD in vivo would workin the above ex vivo or IEC models by inhibiting and/or neutralizing theproduction and/or presence of inflammatory mediators.

In this model, human intestinal tissue is collected from patients withIBD or from healthy controls undergoing intestinal biopsy, re-sectioningor from post-mortem tissue collection, and processed using amodification of Alexakis et al. (Gut 53:85-90, 2004). Under asepticconditions, samples are gently cleaned with copious amounts of PBS,followed by culturing of minced sections of tissue, in the presence ofcomplete tissue culture media (plus antibiotics to prevent bacterialovergrowth). Samples from the same pool of minced tissue are treatedwith one of the following: vehicle (PBS); recombinant human (rh) IL-17A;rhIL-17F; or rhIL-17A+rhIL-17F. In addition, these are treated with orwithout a soluble polypeptide of the present invention, such as asoluble IL-17RC polypeptide or a soluble IL-17RC/IL-17RA polypeptide(SEQ ID NO:158). This experimental protocol is followed for studies withhuman IEC lines, with the exception that cells are passaged fromexisting stocks. After varying times in culture (from 1 h to severaldays), supernatants are collected and analyzed for levels ofinflammatory mediators, including those listed above. In samples frompatients with IBD or in samples treated with rhIL-17A and/or F, levelsof inflammatory cytokines and chemokines are elevated compared tountreated healthy control tissue samples. The addition of a solublepolypeptide of the present invention markedly reduces the production ofinflammatory mediators, and thus, would expect to be efficacious inhuman IBD.

An additional arm of this study can include comparisons of theproduction of inflammatory mediators from tissue biopsies of IBDpatients undergoing effective treatment, and those either not currentlytaking medications or considered non-responders to treatment.

Example 45 Efficacy of the Soluble IL-17RC and IL-17RC/IL-17RAPolypeptides in Human IBD Samples via Epithelial Barrier Function

Maintenance of epithelial barrier integrity is a critical factor in thepreservation of a healthy gastrointestinal tract. Experimental evidencesuggests that leakiness of the epithelial barrier in the gut maycontribute to the development of IBD. Immune cells located in theintestinal lamina propria generally interact with intestinal epithelialcells via cell to cell contact or production of soluble factors tomaintain immune surveillance and contribute to epithelial barrierintegrity. However, prolonged or dysregulated immune-mediatedinflammation may contribute to defects in epithelial barrier cellintegrity and function. The following study is designed to measure thedirect effect(s) of T cell-derived IL-17A and/or IL-17F on epithelialbarrier integrity.

In this example, intestinal epithelial cell lines, like Caco-2 cells,are differentiated on semipermeable membranes and co-cultured on thebasolateral side with either T cells or monocytes derived from biopsiesfrom IBD patients or normal individuals. Epithlelial monolayer integrityis monitored over time using assessment of transepithelial electricalresistance or resistance of the monolayer to dye diffusion. Decreases intransepithial resistance of monolayers in co-cultures would suggest adisruption in the monolayer induced by the activity of the T cells ormonocytes in the co-culture. Inhibitors of IL-17A and IL-17F such as thesoluble polypeptides of the present invention, such as a soluble IL-17RCpolypeptide or a soluble IL-17RC/IL-17RA polypeptide (SEQ ID NO:158)could be used to determine the relative contribution of IL-17A andIL-17F to the disruption of the epithelial monolayer and test whetherinhibitors of IL-17A and IL-17F would be effective in maintainingepithelial barrier integrity. Prevention of epithelial monolayerdisruption induced by activated T cells by such molecules would suggestthat the soluble IL-17RC and IL-17RC/IL-17RA polypeptides of the presentinvention may be effective for the therapeutic treatment of IBD inhumans.

Co-culture systems could also be generated using monolayers formed byprimary epithelium from IBD patients to determine whether these cellsare more sensitive to IL-17A and IL-17F compared to epithelial cellsderived from healthy individuals. If so, these data would suggest thatinhibiting IL-17A and IL-17F would be a suitable strategy for thetherapeutic treatment of IBD.

Example 46 Effects of IL-17A and IL-17F on Lamina PropPria T cells andMonocytes/Macrophages from Normal and Human IBD Samples

Dysregulated or sustained immune-mediated inflammation may contribute tothe symptoms and pathology associated with IBD by way of tissue damageor permanent skewing to inappropriate or prolonged immune responses.This model can determine the potential down-stream consequences ofexposure of disease-associated T cells and monocytes to IL-17A andIL-17F which may be present in the immediate environmental cytokinemileu of the intestinal tissue.

Therapeutics that would be efficacious in human IBD in vivo would workin the above ex vivo models by inhibiting and/or neutralizing theproduction and/or presence of inflammatory mediators (including but notlimited to IL-1β, IL-4, IL-5, IL-6, IL-8, IL-12, IL-13, IL-15, IL-17 Aand F, IL-18, IL-23, TNF-α, IFN-γ, MIP family members, MCP-1, G- andGM-CSF, etc.).

In this model, T cells and monocytes/macrophages are isolated frombiopsy samples by carefully mincing biopsies with scissors in HBSS,treating with collagense and Dispase II and incubating for 1 hr at 37°C. in a shaker. The cell suspension is filtered through nylon mesh toremove debris and cell clumps and washed multiple times in HBSS. T cellsand macrophage/monocytes can be isolated using direct cell sorting orbead-depletion/enrichment protocols. Isolated cells are incubated in thepresence of IL-17A and IL-17F. This induces the production ofinflammatory mediators by T cells and monocytes/macrophages or resultsin skewing subsequent T cell responses to highly pro-inflammatoryresponses. Comparisons between the types of inflammatory mediatorsproduced by cells from IBD patients and those from cells of normalindividuals can be made and might suggest that T cells andmonocyte/macrophages from IBD patients produce a more pro-inflammatoryprofile in the presence of IL-17A and IL-17F. The addition of a solublepolypeptide of the present invention, such as a soluble IL-17RCpolypeptide or a soluble IL-17RC/IL-17RA polypeptide (SEQ ID NO:158) toneutralize the production of downstream inflammatory mediators inducedby IL-17A and IL-17F suggests that such soluble IL-17RC andIL-17RC/IL-17RA polypeptides may be efficacious in the therapeutictreatment of patients with IBD.

Example 47 Efficacy of the Soluble IL-17RC and IL-17RC/IL-17RAPolypeptides in Irritable Bowl Syndrome (“IBS”): CNS-DirectedPathogenesis

A model focusing on primary CNS-directed pathogenesis of IBS whichemploys stress stimuli to induce symptoms characteristic of IBS. Theneonatal psychosocial stress model mimics some clinical featuresassociated with IBS patients including visceral hyperalgesia, diarrheaand stress-sensitivity. Daily separation of the litter from theirmothers for 180 minutes each day during postnatal days 4-18 will resultin an alteration of maternal behaviour and significantly reduce times ofthe licking/grooming behaviour. The stress on the neonates results inpermanent changes in the CNS resulting in altered stress-inducedvisceral and somatic pain sensitivity. Colonic motor function inresponse to stress is enhanced in these animals and preliminary datashows evidence of increased intestinal permeability (Mayer et al.,2002). Treatment with a soluble polypeptide of the present invention,such as a soluble IL-17RC polypeptide or a soluble IL-17RC/IL-17RApolypeptide (SEQ ID NO:158) and subsequent analysis of colonic motorfunction, epithelial permeability and response to stress stimuli coulddetermine efficacy in this animal model of IBS. Decreases in theincidence of symptoms following treatment with these inhibitors wouldsuggest potential efficacy in the treatment of IBS.

Example 48 Efficacy of the Soluble IL-17RC and IL-17RC/IL-17RAPolypeptides in Irritable Bowl Syndrome (“IBS”): Primary Gut-DirectedInducers of Stress

This is a model focusing on primary gut-directed inducers of stress (ie.gut inflammation, infection or physical stress). Animal studies haveindicated that low-grade inflammation or immune activation may be abasis for altered motility, and/or afferent and epithelial function ofthe gut (Mayer et al., 2002). In this model, daily colon irritation isproduced in neonatal animals (days 8-21) in the form of dailyintracolonic injection of mustard oil. Mustard oil is a neural stimulantand has been shown to induce visceral hyperalgesia followingintracolonic administration. This model mimics key features of the IBSincluding visceral hypersensitivity and alteration in bowel habits.Animals also present with diarrhea or constipation, a key feature of IBSpatients (Mayer et al., 2002; Kimball et al., 2005). A solublepolypeptide of the present invention, such as a soluble IL-17RCpolypeptide or a soluble IL-17RC/IL-17RA polypeptide (SEQ ID NO:158)could be delivered to determine changes in the development of symptomsassociated with this model. Decreases in the incidence or magnitude ofvisceral hypersensitivity and altered gut motility following therapeutictreatment with our inhibitors would suggest a potential for thesemolecules to be efficacious in the treatment of IBS.

Example 49 Designing a Scalable Protein Production Process for a SolubleIL-17A and IL-17F Antagonist

In designing strategies focused on developing a scaleable proteinproduction process for a soluble form of IL-17RC, many difficulties wereencountered with identifying an expression system that allowed highlevel protein concentrations in the conditioned media. Western blotanalysis demonstrated low levels of protein secretion with proteinaccumulating in the cell. In the discovery of the soluble polypeptidesof the present invention, more than seventy different expressionconstructs were designed, generated, and tested for expression in eitherBHK cells, CHO cells, or HEK 293 cells. Several were tested in more thanone host cell lines. Variations of tested soluble IL-17RC expressioncassette included:

-   -   1) Alternative signal sequences such as: a) native; b) otPA; c)        mouse immunoglobulin heavy chain variable region; d) human        growth hormone; e) mouse IL17RA.    -   2) Two different naturally occurring splice variants (IL-17RCx1,        SEQ ID NO:2; and IL-17RCx4, SEQ ID NO:166).    -   3) Addition of linker sequences between the IL-17RC        extracellular domain (ECD) and the Fc portion, such as: a) no        linker; b) a 9 amino acid linker based on GlyGlyGlySer; and c) a        20 amino acid linker based on GlyGlyGlySer. 4) His tagged        monomeric forms.    -   5) Both amino- and carboxyl-terminal Fc fusion proteins.    -   6) Removal of N-linked carbohydrate attachment sites.    -   7) Gln for Asn amino acid substitutions.    -   8) Hybrid fusion proteins between IL17RA and IL17RC

All of the soluble IL-17RC variant expression constructs were tested forprotein expression by transient transfection in HEK 293 cells. Westernblot analysis was used to detect protein secreted into the conditionedmedium compared to protein retained in the cell by sampling celllysates. Most of the constructs expressed protein secreted into theconditioned medium that was barely detectable by Western Blot.Additionally, the signal was greater from the cell lysate sample incomparison to the conditioned media sample indicating an inability forthe protein to be efficiently secreted. Those expression constructs thatresulted in the highest signals in the conditioned media were used totransfect stable CHO cell pools. Protein titers were measured from thestable CHO pools and where possible, purified protein was analyzed forIL-17A and IL-17F binding in a cell based competition binding assay. Thefollowing table shows protein expression results from the highestexpressing constructs in CHO cell stable pools. Where absolute proteinconcentration measurements were below the level of detection, theprotein titer is indicated as <0.5 mg/mL.

IL-17RC and IL-17RC/RA protein expression constructs number designation,brief description of exons included, protein titer from stablytransfeced CHO cell pools, and IL17A and IL17F binding ability. Not allthe sequences of the variants included in Table 14 were includedherewith.

TABLE 14 Protein Titer Description (mg/L) Binding x1 splice variant 3.0Ability to Block IL17A IL17RC exons 1-6, and IL17F exons 8-16 (Variant1210) X4 splice variant <0.5 Unable to obtain IL17RC exons 1-16 enoughsample IL17RC exons 1-6 <0.5 Inactive IL17RC exons 8-13 1.6 InactiveIL17RC exons 7-16 <0.5 Ability to Block IL17A (Variant S10) and IL17FIL17RA exons 1-10 32.5 Ability to Block IL17A IL17RC exons 8-16 andIL17F (Variant 1407) IL17RA exons 1-6 <0.5 Inactive IL17RC exons 8-16IL17RA exons 7-10 IL17RA exons 1-3 <0.5 Unable to obtain IL17RC exons4-16 enough sample IL17RA exons 1 <0.5 Unable to obtain IL17RC exons2-16 enough sample IL17RA exons 1-6 19 Ability to Block IL17A IL17RCexons 8-16 and IL17F (Variant 1454)

Example 50 Determination of Amino Terminal Sequence of IL-17RA/RC-Fc5

Protein Expression:

An expression construct containing DNA encoding

IL17RA/RC-Fc5 (SEQ ID NO:157, encoding the amino acid sequence of SEQ IDNO:158) was used to transfect CHO DXB-11 cells. IL17RA/RC-Fc5 proteinwas purified from conditioned media harvests by Protein A affinitychromatography followed by size exclusion chromatography.

N-terminal Amino Acid Sequence Analysis:

Standard automated N-terminal polypeptide sequencing (Edman degradation)was performed using reagents from Applied Biosystems. N-terminalsequence analysis was performed on a Model 494 Protein Sequencer System(Applied Biosystems, Inc., Foster City, Calif.). Data analysis wasperformed with SequencePro Protein Sequencing Analysis Software, version2.0 (Applied Biosystems). Sample preparation included loading 100picomoles (pmol) of the sample onto a precycled filter.

N-terminal sequence analysis of the IL-17RA/RC-Fc5 samples (lots A1672F,A1774F, and A1776F) yielded a sequence starting at L33 (Leucine).

Example 51 Treatment of Oxazalone Colitis with the Murine SurrogateMolecule, Soluble Murine IL-17RA-Fc

The following oxazalone colitis studies were performed in femaleC57BL/10 mice (˜20 g). Mice are sensitized with cutaneous oxazolone (3%in 100% ethanol) on day −5, followed by intra-rectal challenge with1.25% oxazolone in 50% ethanol on day 0. Mice develop acute colitis overthe next 2-3 days. They are typically euthanized and tissues harvestedon day 2.

Two independent oxazalone colitis studies were performed to determine ifsoluble murine (m) IL-17RA-Fc treatment can show efficacy in a murineoxazolone-induced colitis that resembles human ulcerative colitis. ThemIL-17RA-Fc protein is an appropriate surrogate to the IL-17RC andIL-17RA/RC proteins described herein, since mIL-17RA-Fc can both andneutralize murine IL-17A and IL-17F, which is a similar feature of humanIL-17RC and IL-17RA/RC being able to bind human IL-17A and IL-17F.

Results from the first study indicated that treatment with mIL-17RA-Fcresulted in a significant (p<0.05), ˜2-fold reduction in disease indexscore (includes weight loss, stool consistency and blood in stool)versus oxazalone-mice treated with PBS. Treatments were administereddaily as 100 μg, i.p. from either day −6 or day −1 of the oxazalonecolitis model to day 1. The group of mice treated with mIL-17RA-Fc alsohad fewer improved histology scores and less severe colitis-inducedcolon shortening compared to oxazalone colitis mice treated with PBS.

In the second study, mice were treated daily with PBS or mIL-17RA-Fc(100 μg, i.p.) from day −6 to day 1 of the model, and includedappropriate oxazalone-vehicle controls (ethanol only). In addition,groups of mice were included that were allowed to recover from colitisfor 7 days following the challenge, to evaluate whether mIL-17RA-Fc mayaffect this phase of the model. Results indicated that there was asignificant ˜3-fold reduction (p<0.05) in disease index score withsoluble murine IL-17RA-Fc1 treatment administered daily from day −6 today 1 of the model. The incidence of noticeable lesions at day 2 wasreduced in oxazalone mice (37.5% of mice) treated with mIL-17RA-Fc1compared to oxazalone PBS-treated mice (75% of mice). In addition, therewere improvements in histology scores and less severe (p<0.05)colitis-induced colon shortening in mice treated with mIL-17RA-Fccompared to oxazalone colitis mice treated with PBS. There were nodifferences in the 7-day recovery groups, as all mice had recovered bythis time point. In colon cultures (colon piece incubated for 24 h at 37degrees C.) obtained from oxazalone mice at Day 2 of the model, allinflammatory cytokines/chemokines evaluated were elevated compared tovehicle (ethanol) mice. Treatment with mIL-17RA-Fc in oxazalone miceresulted in lower colonic production of IL-17A, IL-17F, TNF-α, IL-1β,IL-4, IL-12, GM-CSF, and IFN-γ compared to levels in PBS-treatedoxazolone mice. Concentrations of colonic IL-17A and IL-17F weresignificantly correlated with each other (R=0.93; p<0.000001).Concentrations of IL-17A and IL-17F were significantly correlated withlevels of TNF-α (R=0.91 and 0.95; p<0.0000001), IL-1β (R=0.64 for both;p<0.01); IFN-γ (R=0.71 and 0.72; p<0.01), and IL-6 (R=0.57 for both;p<0.05). Disease index scores were correlated with colonic production ofIL-17A (R=0.70; p<0.01), IL-17F (R=0.72; p<0.01), TNF-α (R=0.76;p<0.001), IL-4 (R=0.59; p<0.05); IL-1β (R=0.50; p<0.05); and IFN-γ(R=0.52; p<0.05)

In summary, treatment with a surrogate (e.g., mIL-17RA-Fc) to humanIL-17RC and IL-17RA/RC proteins described herein reduces colitis diseasesymptoms, reduces colonic production of inflammatory cytokines, andimproves pathology. These results indicate that the use of humanIL-17-RC or IL-17RA/RC proteins as described herein is efficacious inthe treatment of human IBD.

Example 52 Effect of Mouse IL-17F Overexpression in Murine Models ofDisease

Transgenic mice overexpressing IL-17F gene under the control of ahematopoietic cell-specific promoter (the EuLck promoter) were producedusing methods as substantially described herein (see Production ofTransgenic Mice, Section (K), supra).

Ratio of serum IL-17A to IL-17F in IL-17F Transgenic Mice is Similar toHumans:

Mice that overexpressed murine IL-17F on the EuLck promoter were foundto have markedly elevated serum levels of IL-17F (approximately 2 ng/mL)compared to levels found in wild-type mice (levels non-detectable), asmeasured by an in-house developed Luminex-based assay. Serum levels ofIL-17A were approximately 10-fold lower than IL-17F levels in the IL-17Ftransgenic mice (˜0.2 ng/mL). Thus, the ratio of IL-17A:F in thetransgenic mice was ˜1:10. In wildtype mice, there was only detectableserum IL-17A (˜0.1 ng/mL). This observation of markedly higher (e.g.,10-fold) IL-17F serum levels than IL-17A levels is what is typicallyobserved in humans with autoimmune diseases, thus supporting the use ofIL-17F transgenic mice to study the role of IL-17F in mouse models ofhuman disease, such as multiple sclerosis and arthritis.

Experimental Allergic Encephalomyelitis (EAE) Studies:

Two independent studies were performed to evaluate the effect of IL-17Foverexpression in a mouse model of human multiple sclerosis,specifically murine experimental allergic encephalomyelitis (EAE).Female C57BL/6 wild-type littermate control mice or EuLck IL-17Ftransgenic mice on the C57BL/6 background (˜20-22 g each) were immunizedwith MOG35-55/Ribi (Study 1) or MOG35-55/CFA (Study 2) adjuvant on day0, followed by i.v. pertussis toxin on day 2. Mice were weighed andscored daily for clinical symptoms of disease (e.g., tail and limbparalysis). Results from both studies indicated that IL-17F transgenicmice had a significant (p<0.05) increase in disease onset and severitycompared to wild-type mice. In Study #1, transgenic mice had an earlierpeak of disease that averaged a 36% higher disease severity score thanwild-type mice. In Study #2, the IL-17F transgenic mice had diseaseseverity scores that were 50-70% higher than wild-type littermatecontrol mice.

Collagen Induced Arthritis (CIA) Studies:

Two independent studies were performed to evaluate the effect of IL-17Foverexpression in a mouse model of human rheumatoid arthritis,specifically murine collagen induced arthritis (CIA). Male C57BL/6wild-type littermate control mice or EuLck IL-17F transgenic mice on theC57BL/6 background (˜23-28 g each) were immunized, via tail injections,with chick Type II collagen in CFA, followed by chick Type II collagenin IFA three weeks later. Mice were scored daily for clinical symptoms(i.e., paw swelling) of disease. Results from both studies indicatedthat IL-17F transgenic mice had a significant (p<0.05) increase(˜2.5-3-fold) in disease onset and severity compared to wild-typelittermate control mice.

Example 53 Pharmacokinetics of Murine IL-17RA-Fc, Human IL-17RC-Fc, andHuman IL-17RA/RC-Fc

Three independent pharmacokinetic studies were performed with varioussoluble IL-17 receptors, including the murine surrogate (mIL-17RA-Fc) tothe human soluble IL-17RC and IL-17RA/RC receptors. For these studies,female C57BL/6 mice were obtained from Charles River Labs. Animals werechecked for health on arrival and group-housed (5 animals per cage). Themice were 10-12 weeks old with an average body weight of approximately20 g at the beginning of the study.

A) Dosing Protocol

For each of the three studies, mice (n=24/dose group) were randomlyplaced into a designated group for a specified route of administration:intravenous (i.v.), intraperitoneal (i.p.) or subcutaneous (s.c.; atscruff of neck). Each group of mice was administered the appropriateprotein via the assigned route of administration in a volume of 100 μL.

B) Sample Collection

Prior to blood collection at various time points (from 0.25 to 336hours), mice were fully anesthetized with halothane or isofluorane.Blood samples were collected via cardiac stick for all time points.Blood was collected into serum separator tubes and allowed to clot for15 minutes. Samples were subsequently centrifuged for 3 minutes at14,000 rpm. Following centrifugation, aliquots of 125-150 uL weredispensed into labeled eppendorf tubes and immediately stored at −80° C.until analysis.

C) Results

Murine IL-17RA-Fc Pharmacokinetic Study:

Half-life for i.v. administration was 61 h; 70 h for i.p.administration; and 69 h for s.c. dosing. I.P. dosing was 100%bioavailable; s.c. was 67%. The volume of distribution was 6.7, 8.7, and10.3 mL for i.v., i.p. and s.c. routes, respectively. The longest timepoint for data collection was 120 h post-dosing; serum levels ofmIL-17RA-Fc1 had not returned to basal levels by this time. Subsequentpharmacokinetic studies (summarized below) were carried out to 336 h.

Human IL-17RC-Fc Pharmacokinetic Study:

Half-life for i.v. administration was 72 h; 64 h for i.p.administration; and 54 h for s.c. dosing. I.P. and s.c. dosing were 100%bioavailable. The volume of distribution was 2.7, 2.4, and 2.2 mL fori.v., i.p. and s.c. routes, respectively.

Human IL-17RA/RC-Fc (Variant 1454) Pharmacokinetic Study:

Half-life for i.v. administration was 46 h; 49 h for i.p.administration; and 52 h for s.c. dosing. I.P. dosing was 100%bioavailable; s.c. was 69%. The volume of distribution was 1.7, 2.2, and3.5 mL for i.v., i.p. and s.c. routes, respectively.

Example 54 Therapeutic Efficacy of the Murine Surrogate Molecule,mIL-17RA-Fc, in the Treatment of Graft Verus Host Disease (GVHD)

Graft-vs-host disease (GVHD) is a complication that is observed afterstem cell or bone marrow transplant, or following transfusions of bloodor blood components, most commonly in immunocompromised patients.Although most common following allogeneic transplant, GVHD also occurswith lower frequency following syngeneic and autologous transplant. GVHDcan occur in immunocompetent patients who receive blood from a donor whois homozygous for an HLA haplotype for which the patient isheterozygous. The condition results from the engraftment ofimmunocompetent donor lymphocytes contained in the transplant, whichbecome activated and proliferate in response to host antigens. Theseinfection-fighting cells then attack tissues in the host's body. GVHD istraditionally categorized as acute when it occurs within the first 100days after transplantation and chronic if it occurs more than 100 daysafter transplantation. Tissues typically involved include the liver,gastrointestinal tract, and skin; significant inflammation can occur.

The incidence of GVHD increases with increasing degree of mismatchbetween donor and recipient HLA antigens, increasing donor age, andincreasing patient age. Estimates of occurrence range from 20% to 70%,depending on these and other parameters. However, the disease may beunderdiagnosed and underreported.

Symptoms of acute GVHD include rash, yellow skin and eyes due toelevated concentrations of bilirubin, and diarrhea. Acute GVHD is gradedon a scale of 1 to 4; grade 4 is the most severe. Chronic GVHD maydevelop de novo or by progression from acute GVHD. Symptoms vary morewidely than those of acute GVHD and are similar to various autoimmunedisorders. Some symptoms include dry eyes, dry mouth, rash, ulcers ofthe skin and mouth, joint contractures (inability to move jointseasily), abnormal test results of blood obtained from the liver,stiffening of the lungs (difficulty in breathing), inflammation in theeyes, difficulty in swallowing, muscle weakness, or a white film in themouth. Other symptoms of GVHD include tissue damage (including gut,skin, liver and, in severe cases, lung and kidney) and sepsis-likesymptoms caused by increased levels of circulating inflammatorycytokines (“cytokine storm”). In some severe instances, GVHD can befatal.

First-line treatment of GVHD includes steroid (e.g., methylprednisolone)therapy. Chronic GVHD is treated with a combination of steroids andcyclosporin A. Side effects of steroid immunosuppression includeincreased rates of infection and secondary malignancies, which can befatal. Current treatments may also interfere with the graft-versus-tumoractivity of transplanted donor cells. In view of these serious sideeffects, more selective therapeutic agents are needed.

IL-17RC and IL-17RA/RC proteins described herein are expected to beefficacious in GVHD and/or transplantation. It has been reported thatIL-17A (and most likely, IL-17F) levels are elevated in serum and urineof patients and animal models of transplant rejection. Therefore,neutralization of IL-17A and IL-17F with soluble human IL-17RC orIL-17RA/RC proteins would result in better outcome(s) of GVHD and/ororgan transplantation.

Efficacy of a murine surrogate (mIL-17RA-Fc) to human IL-17RC andIL-17RA/RC proteins were evaluated in a mouse model of acute GVHD (Durieet al., J. Clin. Invest. 94:1333-1338, 1994). Parental mice (C57BL/6;n=12) were euthanized, and their spleens were collected. The pooledspleens were smashed using two glass slides to dissociate splenic cells.Lysis buffer was added to the splenocyte suspension to remove red bloodcells. The cells were washed in RPMI 1640 (10% FBS) medium andresuspended in an appropriate amount of PBS to make a cell concentrationof 300 million cells/ml. Recipient mice (C57BL/6 XDBA/2 F1) were dividedinto treatment groups (PBS or mIL-17RA-Fc). Murine IL-17RA-Fc treatmentswere administered by intraperitoneal injection (150 μg per injection)every other day beginning on day −1 and continuing until day 15. On day0, 80 million donor splenic lymphocytes from B6 mice were injectedintravenously into recipient mice (C57BL/6×DBA/2 F1 (BDF1); n=10 pergroup) mice. Mice were monitored 3 times a week for changes in bodyweight (a hallmark sign of worsening disease in this model) and anysigns of moribundity. Mice that lost >20% of their initial body weightwere euthanized. Otherwise, mice were sacrificed 12-18 days after thecell transfer, and spleen and blood collected.

Spleens were stained for T- and B-cell markers, including MHC class Imarkers (H2^(b) and H2^(d)) to look at donor/recipient cell ratio (acuteGVHD spleen cells are mostly donor cells). Sera were collected tomeasure serum level of IgG1, IgG2a, and IgE by ELISA, and cytokine andchemokine levels using a commercially available kit (LuminexCorporation, Austin, Tex.).

Results of two independent studies showed a correlation of the animalmodel with development of acute GVHD. There was a loss of host (BDF1)spleen cells and decreased numbers of donor (C57BL/6) Treg cells in PBScontrols. In the treated animals, mIL-17RA-Fc treatment maintained hostspleen cells, CD4⁺ T cells, and Treg cells. No treatment prevented theactivation or expansion of donor (C57BL/6) conventional CD4⁺ T cells.All groups had similar numbers of donor conventional CD4⁺ T cells, andGITR (glucocorticoid-induced tumor necrosis factor receptorfamily-related gene) was upregulated by donor conventional CD4⁺ T cells.In both studies, body weight loss in IL-17RA-Fc treatment groups was notsevere and there was significantly less body weight loss in both studies(p<0.05) than in PBS controls (Study #2; see FIG. 6). IL-17RA-Fctreatment did not prevent splenomegaly on the basis of spleen:bodyweight ratio, but treatments did reduce the disease-mediated increase inspleen cell numbers in Study #2, compared to PBS-treated controls(2-fold lower numbers; p<0.01). In Study #1, mice treated withmIL-17RA-Fc had significantly higher serum concentrations of IL-10(˜2-fold higher; p<0.05) compared to PBS-treated controls (IL-10 isthought to be primarily an anti-inflammatory cytokine). In Study #2,mice treated with mIL-17RA-Fc had significantly lower serumconcentrations of TNF-α, and IFN-γ. In both studies, mIL-17RA-Fctreatment resulted in a significantly lower percentage of hostgranulocytes (˜2.5-fold lower; p<0.001).

In summary, treatment with the murine surrogate (mIL-17RA-Fc) of IL-17RCand IL-17RA/RC proteins described herein resulted in therapeuticefficacy in a murine model of GVHD. These results indicate that the useof human IL-17RC and IL-17RA/RC proteins as described herein isefficacious in the treatment of GVHD and transplant rejection.

Example 55 IL17A-CH6/IL17F-CEE Heterodimer Expression in 293F

Two expression plasmids, encoding IL17A-CH6 (nucleotide and amino acidsequences shown in SEQ ID NOs:186 and 187, respectively) and IL17F-CEE(nucleotide and amino acid sequences shown in SEQ ID NOs:188 and 189,respectively), were each constructed in vector pZMP45 via homologousrecombination in yeast.

The IL17A-CH6 fragment was created with PCR, using a previouslygenerated plasmid containing IL17A as template, the forward primerzc57312 to create a 5′ overlap in pZMP45, and reverse primer zc48893 tocreate a Serine-Glycine linker, the 6× Histidine tag, and a 3′ overlapin pZMP45. The IL17F-CEE fragment was created with PCR, using apreviously generated plasmid containing IL17F as the template, theforward primer zc57314 to create a 5′ overlap in pZMP45, and reverseprimer zc58978 to create a Serine-Glycine linker, the EE tag (EEYMPME;SEQ ID NO:190), and a 3′ overlap in pZMP45. The PCR conditions, usingPlatinum® PCR SuperMix High Fidelity (Invitrogen, Cat. #12532-016), wereas follows: 1 cycle 94° C. for 2 min; 30 cycles 94° C. for 30 sec., 55°C. for 30 sec, 68° C. for 45 sec; then hold at 4° C. The PCR reactionmixtures were then run on a 1% agarose gel with 1×TAE. The correct bandswere excised and purified using Qiagen's gel purification kit (Qiagen,catalog #28704).

Plasmid pZMP45 is a mammalian expression vector containing an expressioncassette having the CMV promoter, Intron A, multiple restriction sitesfor insertion of coding sequences, and an otPA signal peptide sequence,the SV40 terminator, an E. coli origin of replication, and URA3 andCEN-ARS sequences required for selection and replication in S.cerevisiae.

100 μl of electrocompetent yeast cells (S. cerevisiae) were combinedwith 100 of purified DNA from above, mixed with 100 ng of BgIII-cutpZMP45 plasmid, and transferred to a 0.2 cm electroporation cuvette. Theyeast-DNA mixture was electropulsed at 0.75 kV (5 kV/cm), ∞ ohms, 25 μF.To each cuvette was added 1 ml of 1.2M sorbitol, and the yeast wereplated onto a URA-DS plate and incubated at 30° C. After about 72 hours,approximately 50 μL packed yeast cells taken from the Ura+ yeasttransformants of a single plate was resuspended in 100 μL of lysisbuffer (2% Triton X-100, 1% SDS, 100 mM NaCl, 10 mM Tris, pH 8.0, 1 mMEDTA), 100 μL of Qiagen P1 buffer from a Qiagen miniprep kit (Qiagen,Valencia, Calif., catalog #27104), and 20 U of Zymolyase (Zymo Research,Orange, Calif., catalog #1001). This mixture was incubated for 30minutes at 37° C., and the remainder of the Qiagen miniprep protocol wasperformed, starting with the addition of reagent P2. The DNA was elutedwith 40 μL EB reagent.

Fifteen μL electrocompetent E. coli cells (DH12S, Invitrogen, Carlsbad,Calif.) were transformed with 2 μL yeast DNA in a 0.2 cm electroporationcuvette. The cells were electropulsed at 1.75 kV, 25 μF, and 400 ohms.Following electroporation, 1 ml SOC (2% Bacto Tryptone (Difco, Detroit,Mich.), 0.5% yeast extract (Difco), 10 mM NaCl, 2.5 mM KCl, 10 mM MgCl₂,10 mM MgSO₄, 20 mM glucose) was added to the cuvette. This solution wasplated on two LB AMP plates (LB broth (Lennox), 1.8% Bacto Agar (Difco),100 mg/L Ampicillin), one with 200 μL of transformants, the second with100 μL.

Individual clones were picked from the transformation plates, and weresequenced to identify one clone containing the correct expressionconstruct for IL17A-CH6 and one for IL17F-CEE. Larger scale plasmid DNAwas isolated using the Invitrogen mega prep kit (Invitrogen, Carlsbad,Calif., catalog #457009) according to manufacturer's instructions.

Transfection into 293F Cells

To test for expression of the IL17A CH6-IL17F CEE heterodimer, 293Fcells were transiently transfected using Lipofectamine2000 (Invitrogen,Carlsbad, Calif., catalog #11668-019) and OptiMEM (Invitrogen, Carlsbad,Calif., catalog #31985-070) and grown in a 12-well plate. IL17A waspreviously determined to be the less expressed protein of the two, so aDNA ratio of 3 parts IL17A CH6 to 1 part IL17F CEE was used for thetransfection. 2 μg plasmid DNA and one million cells were used for thetransfection. After 96 hours, medium was harvested and prepared for aWestern blot assay.

Invitrogen materials and protocols were used for the Western blot withanti-6× histidine (R&D Systems, Minneapolis, Minn., catalog #MAB050H) asthe detection antibody for IL17A CH6, and with an in-house mouse mAb asthe detection antibody for IL17F CEE, and Jackson HRP-goat anti mouseIgG (H+L) (catalog#115-035-003)+BD Parm. HRP-anti mouse IgG2a (R19-15)(catalog #553391) as the secondary antibodies. Significant expressionwas observed, so a large scale transfection was done for proteinacquisition.

Example 56 Purification of single chain Human IL17A:IL17F Heterodimerfrom CHO DXB11 Cell Culture Expression

Recombinant human IL17A:IL17F heterodimer protein (zcyto40f2 v.2) wasproduced from expression of a single chain construct in CHO DXB11 cellsand cell culture in a WAVE apparatus. The construct was comprised ofsequences for Human IL17A at the N-terminus with IL17F at the C-terminus(construct 1789; C-His tagged) linked with a (G₄5)₃ linker. A His tagwas added to the C-terminus to effect efficient product capture.Approximately 10 L of conditioned media were harvested and sterilefiltered using a 0.2 μm filter. The media was adjusted to pH 5.0 withaddition of acetic acid while stirring. At this point a significantprecipitation process occurred and the pH adjusted media was againfiltered through a two stage 0.8 to 0.2 micron filter (PallCorporation).

Cation Exchange Chromatography

The adjusted media was then loaded, at 10 ml/min, to a pre equilibratedCation exchange column, 16 mL bed volume; 2 cm. dia. (SP Fast Flowresin, GE Healthcare) using an AKTA™ explorer Chromatography platform(GE Healthcare). The equilibration buffer was pH 5.0, 0.02 M Aceticacid, 0.1M NaCl. Upon completing the sample load, the column was washedfor 20 column volumes with equilibration buffer, at which point a stableUV @ 280 nm baseline was obtained.

The bound protein fraction was eluted at a flow rate of 20 ml/minute,collecting 5 ml fractions while forming a 20 column volume gradientbetween equilibration buffer and elution buffer; 0.02, Acetic acid, 1.0MNaCl, pH 5.0. Fractions were analyzed by SDS-PAGE Coomassie and WesternBlot formats. A dense distinct band at 38 k Da was observed in the first(main peak) of two eluate peaks observed during the gradient elution.The main peak transport domain; fractions #20-48 inclusive, exhibitedspecific anti-His tag staining, the entire breadth of Western blotstainable fractions was pooled and moved forward in the process.

IMAC Chromatography (Metal Chelation Affinity Step)

A 5 mL HisTrap IMAC column (GE Healthcare) was equilibrated with 20column volumes of buffer; 0.5 M NaCl, 50 mM NaPhos; 25 mM Imidazole atpH 7.5. The cation exchange pool, 144 ml, was adjusted for IMACchromatography with addition of sufficient solid reagent to bring theconcentration to 25 mM Imidazole. An equimolar mix of mono and dibasicSodium phosphate solutions (0.5 M each) was added to bring the phosphatebuffering to 20 mM, at which point the pH was adjusted to 7.5 withaddition of 2 N NaOH.

The adjusted cation exchange pool is now ready to load to the HisTrapIMAC column. The loading flow rate was 4 ml/min. Upon completing thesample load, the IMAC column was washed with 40 column volumes ofequilibration Buffer prior to step elution with 0.4 M NaCl, 400 mMImidazole pH 7.5 buffer. Soon after switching to the elution buffer, asubstantial peak eluted from the column.

This material was pooled and concentrated to 3 ml for injection to thefinal process step, size exclusion chromatography.

Size Exclusion Chromatography Process

The concentrate from the IMAC step was injected to a pre-equilibratedSuperdex 200 (GE Healthcare; 16/60; 120 ml) SEC column flowing at 1.5ml/min in mobile phase composed of 35 mM Sodium Phosphate Buffer; 109 mMNaCl, pH 7.3. Fractions of 1.5 ml were collected. Some early, low leveleluting materials precede a mostly symmetric peak eluting at 0.7 columnvolumes. Fractions directly preceding and within this main peak wereanalyzed by SDS-PAGE with Coomassie staining. A pool of fractions wasmade to deliver the highest purity product, some fractions containingproduct were excluded due to co-elution with undesirable contaminants.

Analysis of Purified Single Chain Human IL17A:IL17F Heterodimer

Recombinant, single chain Human IL17A:IL17F heterodimer, was analyzed bySDS-PAGE (10% BisTris, Invitrogen, Carlsbad, Calif.) with 0.1% CoomassieR250 staining for protein and after transfer to nitrocellulose, byimmunoblotting with Anti-His-HRP. The purified proteins wereelectrophoresed using an Invitrogen Novex's Xcell II mini-cell, andtransferred to nitrocellulose (0.2 mm; Invitrogen, Carlsbad, Calif.) atambient temperature at 600 mA for 45 minutes in a buffer containing 25mM Tris base, 200 mM glycine, and 20% methanol. The filters were thenblocked with 10% non-fat dry milk in 50 mM Tris, 150 mM NaCl, 5 mM EDTA,0.05% Igepal (TBS) for 15 minutes at room temperature. Thenitrocellulose was quickly rinsed, and the specific HRP conjugatedantibody (1:2500) was added. The blots were incubated overnight at 4°C., with gentle shaking. Following the incubation, the blots were washedthree times for 15 minutes each in TBS, and then quickly rinsed in H₂O.The blots were developed using commercially available chemiluminescentsubstrate reagents (Roche LumiLight), and the signal was captured usingLumi-Imager's Lumi Analyst 3.0 software (Boehringer Mannheim GmbH,Germany.) Non-reducing Coomassie staining analysis revealed a dimericproduct as a doublet, with the lower member predominating.

SDS-PAGE with Coomassie staining analysis for reduced and non-reducedproduct revealed a doublet of disproportionate intensities at theapparent electrophoretic mobility for dimeric polypeptide chain. Theupper band of the doublet being the predominant form observed. ReducingSDS-PAGE and Western blot data exhibited a negligible amount of lowermolecular weight species. N-terminal sequence analysis was run on 100pmol of product. The results indicated a single N-terminus recovered ata repetitive yield of 57.9 pmol with the N-terminal residue being G24,the start of Human IL17A sequence. Amino acid composition data conformedto the theoretical composition. Analytical size exclusion analysisindicated 99+% purity of the product.

Example 57 Measurement of Binding Affinity of IL-17RA/RC-Fc5 to theIL-17A/F Heterodimer Antigen Via Surface Plasmon Resonance (Biacore)

This study was performed to evaluate the binding affinity ofIL-17RA/RC-Fc5 (variant 1454) to the IL-17A/F 2 chain heterodimer.

Affinity Determination

Kinetic rate constants, equilibrium association constants, andequilibrium dissociation constants were measured for the interaction ofIL-17RA/RC-Fc5 with the IL-17A/F heterodimer antigen via surface plasmonresonance. The association rate constant (k_(a) (M⁻¹ s⁻¹)) is a valuethat reflects the rate of the antigen-receptor complex formation. Thedissociation rate constant (k_(d) (s⁻¹)) is a value that reflects thestability of this complex. Equilibrium binding affinity is typicallyexpressed as either an equilibrium dissociation constant (K_(D) (M)) oran equilibrium association constant (K_(A) (M⁻¹)). K_(D) is obtained bydividing the dissociation rate constant by the association rate constant(k_(d)/k_(a)), while K_(A) is obtained by dividing the association rateconstant by the dissociation rate constant (k_(a)/k_(d)). Antagonistswith similar K_(D) (or a similar K_(A)) can have widely variableassociation and dissociation rate constants. Consequently, measuring thek_(a) and k_(d) as well as the K_(A) or K_(D) helps to more uniquelydescribe the affinity of the receptor-antigen interaction.

Materials and Methods

An experiment was completed to measure the binding affinity of thepurified IL-17RA/RC-Fc5 receptor to the human recombinant IL-17A/Fheterodimer. The binding kinetics and affinity study was performed on aBiacore T100™ system (GE Healthcare, Piscataway, N.J.). Methods for theBiacore T100™ were programmed using Biacore T100™ Control Software, v1.1.1. Since the IL-17RA/RC-Fc5 receptor contained a human Fc domain,goat anti-human IgG Fc-gamma (Jackson ImmunoResearch, West Grove, Pa.)was used as a capture antibody for these studies. The capture antibodywas covalently immobilized to a CM4 sensor chip using a mixture of 0.4 MEDC [N-ethyl-N′-(3-diethylamino-propyl) carbodiimide] and 0.1 M NHS(N-hydroxysuccinimide) to a density of approximately 4000 RU. Afterimmobilization of the antibody, the remaining active sites on the flowcell were blocked with 1 M ethanolamine. The IL-17RA/RC-Fc5 receptor wascaptured onto one flow cell of the CM4 chip at an approximate density of90-100 RU. Capture of the receptor to the immobilized surface wasperformed at a flow rate of 10 μL/min. The Biacore instrument measuresthe mass of protein bound to the sensor chip surface, and thus, captureof the soluble receptor was verified for each analysis cycle.

For binding studies with the IL-17A/F heterodimer (IL17A-CH6/IL17F-CEE 2chain heteromdimer as described in Example 55, supra), serial 1:3dilutions of antigen from 33 nM-0.015 nM were injected over the surfaceand allowed to specifically bind to the IL-17RA/RC-FC5 receptor capturedon the sensor chip. Duplicate injections of each IL-17A/F antigenconcentration were performed with an association time of 7 minutes and adissociation time of 15 minutes. Kinetic binding studies were performedwith a flow rate of 30 μL/min. All binding experiments were performed at25° C. in a buffer of 10 mM HEPES, 150 mM NaCl, 3 mM EDTA, 0.05%Surfactant P20 (GE Healthcare, Piscataway, N.J.), 1 mg/mL bovine serumalbumin (Proliant Biologicals, Boone, Iowa), pH 7.4.

Between analysis cycles, the flow cell was washed with 20 mMhydrochloric acid to regenerate the surface. This wash step removed thecaptured IL-17RA/RC-Fc5 receptor from the immobilized antibody surface,and allowed for the subsequent binding of the next test sample. Data wascompiled using the Biacore T100™ Evaluation software (version 1.1.1).Data was processed by subtracting reference flow cell and blankinjections. Baseline stability was assessed to ensure that theregeneration step provided a consistent binding surface throughout thesequence of injections. Duplicate injection curves were checked forreproducibility. The IL-17A/F heterodimer has two potential bindingpartners (IL-17A and IL-17F) for the IL-17RA/RC-Fc5 receptor. If onlyone portion of the heterodimer binds to the receptor, a simple 1:1binding model would be appropriate and the curves should fit well tothis model. However, if both the IL-17A and IL-17F portions of theheterodimer bind to the receptor, the bivalent binding model would beappropriate and the curves should fit this model. The binding curveswere globally fit to both the 1:1 and bivalent analyte binding models.

Results

The IL-17RA/RC-Fc5 receptor was characterized for its binding affinityfor the human IL-17A/F heterodimer antigen. Association rate constants(k_(a) (M⁻¹ s⁻¹)) and dissociation rate constants (k_(d) (s⁻¹)) weremeasured. While the resulting binding curves did not fit the 1:1 bindingmodel, the data fit well to the bivalent analyte model. This result isconsistent with both portions (IL-17A and IL-17F) of the IL-17A/Fheterodimer binding to the soluble receptor. The bivalent analytebinding model measures two values for both k_(a) (k_(a1) and k_(a2)) andfor k_(d) (k_(d1) and k_(d2)). The first set of values (k_(a1) andk_(d1)) describes the monovalent kinetics of the interaction. Theaffinity reported for these samples was derived from these values, andis designated K_(a1) and K_(m) The second set of values (k_(at) andk_(d2)) refers to the avidity of the interaction and was not reported.The measured binding kinetics were 5E+05 (M⁻¹ s⁻¹) for k_(a1) and 2E-03(s⁻¹) for k_(d1), resulting in a calculated K_(a1) of 4E-9 (M) [K_(m) of2E+8 (M⁻¹)]. These values are comparable to the results obtained withthe IL17A/A and the IL17F/F homodimers.

TABLE 15 Binding Affinity for IL-17A/F Heterodimer Antigen k_(a1)(M⁻¹s⁻¹) k_(d1) (s⁻¹) K_(D1) (M) K_(A1) (M⁻¹) IL-17A/F Heterodimer5.E+05 2.E−03 4.E−9 2.E+8

Example 58 IL17A/F Heterodimer Activity and Neutralization byIL-17RA/RC-Fc5

IL17A/F heterodimer constructs (zcyto40f2v.1-2chain and zcyto40f2-singlechain) were tested for activity and IL-17RA/RC-Fc5 neutralization. TheIL-17RC activity assay utilizes the NIH-3T3 cell line transfected withthe KZ170 reporter construct for detection of NFκB mediated detection ofIL-17A and IL-17F signaling in a luciferase reporter assay. Bothheterodimer constructs showed a dose-dependent response in this assay,with EC50 values of 15.19 nM and 20.59 nM for the 2-chain and singlechain constructs, respectively. IL-17A and IL-17F homodimers also showeddose dependent responses, with EC50 values of 2.026 nM and 17.31 nM,respectively.

IL-17A/F heterodimer constructs were also tested in a neutralizationassay utilizing the NIH-3T3/KZ170 luciferase reporter cell-based assay.The soluble receptor IL-17RA/RC-Fc5 (variant 1454) was titrated with aconstant concentration of ligand and tested in the reporter bioassay.Both heterodimer constructs were neutralized in a dose dependent mannerby the IL-17RA/RC-Fc5 soluble receptor, with IC50 values of 3.169 nM and13.34 nM for the 2-chain and single chain constructs, respectively.IL-17A and IL-17F homodimers were also neutralized in a dose dependentmanner, with IC50 values of 0.1673 nM and 0.8735 nM, respectively.

From the foregoing, it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. All publications, patents, andpatent applications cited herein are hereby incorporated by reference intheir entireties for all purposes.

1. An antibody, or antibody fragment, that specifically binds to a polypeptide comprising amino acid residues 33-458 of SEQ ID NO:
 158. 2. The antibody of claim 1, wherein the antibody, or antibody fragment, is selected from the group consisting of a polyclonal antibody, a murine monoclonal antibody, a humanized antibody derived from a murine monoclonal antibody, an antibody fragment, a neutralizing antibody, and a human monoclonal antibody.
 3. The antibody fragment of claim 2, wherein the antibody fragment is selected from the group consisting of F(ab′)₂, F(ab)₂, Fab′, Fv, scFv, and minimal recognition unit.
 4. An anti-idiotype antibody that specifically binds to the antibody of claim
 1. 5. A diagnostic kit comprising at least one container comprising the antibody, or antibody fragment, of claim
 1. 6. The diagnostic kit of claim 5, further comprising a second container comprising one or more reagents capable of indicating the presence of the antibody, or antibody fragment. 